I live in Eugene, though I'm not going to attend U of O (UVA is looking better). However, Eugene is really nice. There are tons of community garden spaces and bike paths, and a river bike path allows you to live in the hipper neighborhoods yet have a commute that is almost entirely car-less. If you live in the Whiteaker neighborhood, around 1st and van buren, you can find cheap housing *and* be around great little restaurants and bars and one of the most progressive community credit unions in the state (O.A.R. Credit Union). Also, Eugene is organized into neighborhood communities that handle community governance and get folks involved in local politics. It is a very active town in a local political sense. My neighborhood, Whiteaker, is working on initiatives to curb urban sprawl, create a quiet zone for the railroad, increase public safety with more bicycle cops, etc.
I love Eugene, love my awesome 2-bedroom house that is a block from the river, has great neighbors, and costs $665 a month with pets and a huge backyard, love the kindness and helpfulness of everyone at the community gardens, love the town-wide Eugene celebration in September and incredibly funky July Oregon Country Fair out in the boonies.
Downsides: Although it's good-sized, Eugene is not a big city. it's a college town. The airport is expensive, so one tends to take the train or drive to Portland for flights. (it's not a bad idea to join United and start racking up the frequent flier miles if you want to save on flights out of Eugene). Your big band favorites will often go to Portland and not Eugene. The town is mostly white, except in the Whiteaker neighborhood, which has a name for being rough b/c it's where you will actually see a black person. It rains or is cloudy or is drizzly all early spring, like Feb-April. I'm serious, that last one is a deal-breaker for me. I need the sun! There are also lots of bike thefts, and sometimes too many hippies just pisses me off.
However, if you like a town with an involved and active populace, a mild climate (no snow or salt-rust for your car), great hiking and swimming, gardening, terrific public transportation, cheap nice homes (I don't know what neighborhood that person who saw everything falling down was looking at--Eugene has some of the most beautiful permaculture front yards I have ever seen), and a totally blossoming blooming summer season, you will be happy here.
UO's Enviro program is supposed to be hottt. I know in town I am pretty into the Lane county legal aid and elder law services they provide, as well as the domestic violence legal clinic. Those are good hook-ups for practical work.
Hope this helps! i am willing to answer questions, also there is a Eugene LiveJournal called, I think, The Friendly Eugene, that can help with town-specific questions.