The 2.6Ghz Quad with 16GB RAM and a Fusion drive will cover everything you want to do. Just by coincidence, it will also cost you the most.
But I warn you, you will now get a whole bunch of forum members who do not own the 2.6Ghz telling you you don't need it
Don't listen to them
It is sort of like someone driving a Toyota Prius telling you you do not need a Ferrari to get from A-Z. True, but hey... it is a lot more fun in a Ferrari and you get there so much quicker!
You can save a few dollars with getting your own RAM. I use two 8GB Corsair Vengeance chips (16GB total). It is very easy to install.
If you are adventurous you can also do your own hard drive install such as an SSD (instead of getting it from Apple). But if you are use to doing that on PCs, it is nothing like the install on a mini.
See the OWC website or iFixit if you want to see if that is your cup of tea.