The best thing about Carleton is by far the students. I've already mentioned the accepting, intellectual, and silly atmosphere and I think if you're looking for that, you'll feel at home.
The professors are also amazing. There are definitely a few who aren't quite as good as others, and there's always a risk with taking a class from a new prof, but on the whole they are incredible! I'm always blown away by their level of knowledge and ability to address tough issues in the texts. The best way to ensure a good class is to talk to people and find out who they like, who they don't like, and who they've had a life changing experience taking a class from!
The small size of Carleton (and of Northfield) is both a good and bad part of the Carleton experience. One the on hand, you walk around and see tons of people you know, you know most of the professors in your department, you know most of the kids in your classes, and you often can get into things like theater, music, and other organizations without having to worry about people majoring in them taking all the spots (this gives you a chance to build up some skills in this stuff!). On the other hand, this small size means that Carleton (already plagued by its small town, white, Midwest, and high cost reputation) has extremely low diversity--unless you're white, you'll probably know every single person in your ethnic group by the end of the first term. Alsol, it can sometimes mean a pretty small dating pool, which gets almost miniscule if your gay or lesbian.
Northfield is tiny but with some charm. It has a nice historic mainstreet and a fair amount of individuality. Many people complain that it's too small that there aren't enough places to eat, but then it's a town of 10,000, there were never going to be too many geat places to go (that being said, we have two delicious Indian places, a good sandwich shop, a few pizza joints, and a waffle house. The main bar has a good selection of beer though the prices are a little high). I didn't come to small town Minnesota from LA expecting to find cheap burritos and take out Thai on every corner, I came looking for a place where students put their energy inward to create cool events on campus during the weekends, where I'd have a patch of nature to go exporing--The Carleton arboretum is gorgeous, a wonderful place to go to take a break with a run or to have a work study job restoring native prarie!
The weather is really cold. During the winter, people complain about it more than the food (which is generally pretty terrible, though we're changing our dining service so we'll see . . .)
Winter is frigid and often below zero. However, if your like me and have always wanted to live in a winter wonderland, have snowball fights, go sledding, and learn ice hockey, then it often works out nicely (except when it drops down beyond bearable in February!) We also have beautiful Falls and Springs where all the leaves change or regrow in beautiful unison.