Fort Collins is a cool mid-sized town (I'd say just over 100K ppl) and there are a lot of conveniences. First, decent housing is available close to campus and if you're a bike person you will find Ft. Collins and CSU friendly to bikers. Whatever you do just stay close to campus, its pretty much right in the middle of everything. If you're an outdoorsy person you'll be thrilled with what FoCo and the surrounding areas have to offer and probably won't be bored too much. If you're not an outdoors person the town should still offer enough to do for you to keep busy you just have to seek it out a bit more, depending on what you're into of course. Denver is only 60 miles away if you need a major city for anything (and a fun place to hang out by the way).
People in FoCo will often brag about how many breweries are in the area and hold it up as one of the best beer towns you'll ever encounter. Its true, there are a good amount of breweries but half of them brew crappy beer (in my humble opinion) that half the time make me wanna strangle somebody for a simple bud light. What's more is that they often only have THEIR beers which kills me. But you'll get plenty of New Belgium and O'Dell's which is far from a bad thing (oh, so tasty)! Downtown offers a pretty good assortment of hangouts from a couple dance spots, to pool halls, to an irish pub, etc. Also, away from campus you'll find some cool spots which offer a change from the downtown scene. Honestly, if you know how to have a good time I don't think FoCo will disappoint. Just meet the right people.
The town has an overall good feel to it. I definitely wouldn't say the people are super nice but they're also not excessively rude. As a grad student who lived off campus for two years I feel extremely lucky to have had cool people in my department, otherwise I don't know how I would have made friends. It is these people that allowed me to enjoy this city because I think I may have otherwise been miserable. I'm a pretty clean cut, Latin, warm-blooded city boy from AZ and while nobody ever made me feel unwelcome, I never fully fit in with the FoCo vibe (olus its SO COLD!). Again, not a knock on the place, just didn't mesh so well with it as other people did (many that have ever lived here will tell you its an amazing place). The thought of leaving here in May to return to a warmer climate puts a smile on my face and I won't be rushing back. But, again, that's just me.
Now the reality: this university and this state have SERIOUS education problems in terms of money. Adjuncts are so far underpaid it makes me sick and the university does not offer health benefits to its TAs, which I find rediculous at this point. As a TA I outearned the adjuncts I TA'd for unless they tought multiple courses. Add that to the fact that at least TWO bad budget years are in the future and you'll realize how shaky your funding is. Its unfortunate, but its reality.
I hope that gives you a decent idea. Let me know if there are any specific questions you might have and I'll do my best to oblige.