RAM or flash drive

[SaSaSushi]

...or she can go to the Genius Bar or a service center and get more RAM installed. This isn't a rMBP pro with soldered RAM. It's an iMac that's a tad bit harder to open for the average user. The RAM CAN be upgraded.

Sure, and if you're willing to go that expense, the same can of course be said for the SSD.

 

[yjchua95]

...or she can go to the Genius Bar or a service center and get more RAM installed. This isn't a rMBP pro with soldered RAM. It's an iMac that's a tad bit harder to open for the average user. The RAM CAN be upgraded.

Not by the user.

Do you have any idea how hard it is to tear it apart?

The average Joe doesn't have a heat gun.

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A tad bit? Your joking right? Take a look at ifixits tear down. http://www.ifixit.com/Teardown/iMac+Intel+21.5-Inch+EMC+2638+Teardown/17829

Not something I would do to my machine!

I agree. It's bloody murder to take it apart.

 

[SaSaSushi]

The average Joe doesn't have a heat gun.

Well, you actually don't need a heat gun, because the LCD panel is held on by double-sided tape, not glue. You can use a pizza cutter tool like this one iFixit is selling.

It is no job for the novice though and my advice from the beginning of this thread was with that in mind.

 

[toddzrx]

How exactly will she upgrade the RAM in a few years in a 21" iMac? I doubt she will have the skill or equipment to do that.

Take it to someone that can. While it will cost a lot for the labor relative to the RAM itself, it's certainly possible. And, if the cost of additional RAM extends the usefulness of the machine (for her purposes of course; RAM needs are obviously very user dependent) for another year or two, that's a much cheaper route than just buying a whole new computer.

Besides all of that, the OP was asking an either/or question; I simply agreed with her choice of the SSD as the best value and performance. By all means, if she had the money to do it, I'd have suggested she get the SSD and the extra RAM.