First iMac purchase

Congratulations on becoming a parent in a few months!

I think by the time you upgrade the 21.5" 4K iMac, you might want to look at the 27" 5K iMac. But if you stick with the 4K model, than I'd recommend the following…

RAM: Unfortunately, it is soldered on and you can't add or change it later on. So you definitely want to get 16GB when you buy it.

Processor: Since you want it to last a long time, I'd upgrade to the 3.3 i7 processor.

Storage: Avoid the 1TB 5400 rpm spinner. The 1TB fusion drive has a 24GB ssd along with a standard spinning hard drive. The 2TB fusion drive has a 128GB ssd along with a standard spinning hard drive. I think the 2TB is the way to go.

By the time you do those upgrades, you are very close to the price of the 27" iMac. Here is a review of the 4K 21.5" iMac.

 

If you're anticipating taking lots of pics and video of the new baby (I know I am) you'll likely want more than 512GB of storage – particularly if you’re using a higher MP camera (like a midrange dSLR or mirrorless) or filming anything other than quick clips on your phone. This will mean either adding an external drive at some point - which is cheap and easy but not to everyone’s aesthetic tastes and makes file management a smidge more involved – or going with the Fusion drive.


For the scenario you’ve described, I’d favour the Fusion: “if you don’t know why you need a pure SSD solution, you don’t need a pure SSD solution.”


The 21.5” iMacs DO NOT have upgradable RAM. They have RAM soldered to the mainboard. So what you buy, you’re “stuck” with. But I tend to believe that 8GB is the sweet spot right now for anyone without specific use-cases requiring more, and I don't think it will be too far behind the curve for a "general purpose" machine in 5y.


If a 2008 MB has lasted you until now, and you don’t foresee significant changes in your usage (that is, you’re not going to suddenly start shooting RAW and using Lightroom, you’re just going to be taking MORE photos and using Photo and iMovie more often), then I think you’ll be happy with the 21.5” with the base processor and 8GB.


Note that for $300 more, you can get the 2TB 27” 5K model, which also brings better graphics, user-upgradable RAM, a slightly faster CPU, and a bigger screen. It’s a better machine overall, and the price difference is fair, but if you’re looking to keep price down I think the 21.5” 4K with a 2TB Fusion will suit your usage fine.

 

OP - if you go for the 27" baseline model - it will have 2x4gb RAM which you can upgrade yourself anytime in the future and save money that way. (32gb right now is ~$170 depending on brand)

BTW - 8gb right now - is more that enough for what you are using your computer for.

Storage - just keep in mind - HDD's are not going anywhere soon. in fact 99% of people (i made that number up) are using HDD when adding external drives. You can buy a 5TB external HDD for $165. USB 3 speed - so it's FAST.

By the time people can affordably put a 1TB SSD in a computer - we will be using 10TB external HDD's.

So I suggest - if you can afford an Apple SSD in a computer - get it - but otherwise get a 2TB Fusion Drive - and then when /if you ever need it buy a nice fast USB external drive.

PS - this all goes the same really if you buy the 21" iMac too (minus the RAM upgrade

Good luck!

 

The base model 27" 5K iMac comes with a 1TB 7,200 rpm hard drive, for $1,799. If you want the 2TB fusion drive, it will be an extra $300 for a total of $2,099.

 

Which is $300 more than the 2TB-configured 21.5" I was proposing. But yeah my phrasing was unclear.

 

If you compare these two configs I quickly made up, you'll see for $200 more you're going to get a faster processor, larger screen and MUCH better graphics for $200 more. I don't think OP will need more than base processors and though the 27" lacks 16GB RAM you can upgrade to 24GB (add two 2X8GB) for less than $100 and you'll have more than enough RAM for the end of the decade.

FWIW my mom has the 21.5" iMac and I have the 27" iMac and though her screen is more than adequate, I wouldn't trade my 27" for anything. Though it's not the retina screen it's absolutely beautiful and on certain wallpapers of mine quite frankly it's breathtaking. If you can afford to... get the 27".

 

Realmford, I just purchased a 5k 27" iMac, so my head is still spinning with all of the research that I did. Here's my recommendation for getting a machine that will last 5-7 years. My last iMac was the 2007 24", which I loved, but it was definitely feeling its age. It made it all the way to El Capitan though! So like you I wanted a machine that could make it another 7 years.

If you can stretch the budget I do recommend the 27", mainly for the RAM upgradeability. You get 4 slots that can handle up to 64GB of memory. You'll never need that much in the next 7 years, but I do believe that starting with 16GB now and updating to 32GB at mid-life will be a really nice way to future proof your machine. The general consensus on RAM is only buy the 8GB minimum from Apple and then upgrade yourself to 16GB. When I got my new iMac last week it came with 8GB. I put it to the test with a RAM app called "Memory Clean," which told me how much I was using. With many apps and webpages open the RAM dropped to about 1GB unused. The good news is that everything ran fine with 8, but I still decided to bump the total to 16GB for $50 with Crucial memory (trusted brand). Note: you can only upgrade RAM in the 27", not the 21". If you go with the smaller machine I STRONGLY recommended you buy 16GB from Apple, especially if you intend to use any programs involving video editing, etc.

The 27" has an incredible 5k screen. I'm sure the 4k will be stunning too (for anyone coming from a non-retina screen like the both of us), but if you're laying out money sometimes it's nice to get the very best screen quality. I picked the midrange processor: 3.3 GHz i5 with M395 graphics card. It's plenty fast for me. Some might argue that this is the best place to future proof a computer, but for what I'm using it for I believe I made a good cost conscious choice. We are doing identical tasks too (although I have tons of photos of nieces instead of kids of my own).

Storage is a tough one. I got the 512 SSD because of the speed and the hope that a non spinning drive would last longer (we had to replace the HD in the last iMac). There are probably arguments out there that SSDs break down just as often as the other drives. I take plenty of photos, but only minimal video. You mentioned exploring 4k video, which I don't know much about, but I bet takes up some space. If you think you need more than 512 than definitely go with the 2TB with 128GB SSD. Another option to stay under 512 might be off-loading media to an external drive for long term storage. As mentioned in other posts the USB3 drives are really fast for accessing content and backing up.

Side note about backing up! Maybe I'm paranoid, but I keep a back-up in another location besides the house. I fear in a robbery or a fire if the main computer and the external drives are all lost together than you have nothing. I keep a drive off-site that I back up every other week or so. Keep at work, in a safe deposit box, or with a trusted family member. Just my 2 cents.

If you decide to go with the 21" iMac then definitely max out the specs. I agree fully with all of the advice from Ucfgrad93 (post #2 above) about that purchase.

Last advice: try to lower the cost by using an education/government employee/work discount. I think it shaves off nearly 10%.

Good luck, enjoy the new machine (I'm loving mine probably more than is respectable), and congrats on the growing family!