If you are going to do just the basics, using the standard apps, the base model would probably do.
Do you intend to use Office for Mac, (which runs using OS X), or install Windows to use Office?
How much video editing do you think you will do?
Might you needs change over the near to medium term?
If you are likely to ask a bit more than the basics of your Mini, the next tier up could be the way to to go. It comes standard with 8 GB RAM, a faster processor, better graphics, and a 1 TB HDD. However, there is little point in getting more Mini than you require if your needs don't justify it.
For me, both my Minis have been base models. I usually use iWork (Pages can open Word documents, and export Pages documents as word, with little or no hassle; I do it often. Converting between Numbers and Excel can be done, but not always so successfully; I don't bother). The iLife suite is good for most of the rest of what I do, and I haven't really found myself wanting for more than the base model.
As I am doing more photography now, I would be inclined to go for a mid tier model, possibly custom specced with Fusion Drive or SSD, when the time comes to replace what I have….. which is over six years old already, and has just 5 GB RAM (the original 1 GB plus an extra 4 GB). However, it remains fine for my needs for now (as a teacher), so I don't anticipate replacing it any time soon.
Check out this page:
http://www.apple.com/shop/buy-mac/mac-mini
Try out various configurations, and read the advice offered on what to choose.