Eugene is neat. Fantastic road riding with low traffic and good roads. Hills aplenty in the Coast range and some monstrous climbs in the Cascades. If you like flat roads, there are plenty of them to the north. Racing is plentiful as well. The Twilight series has different types of weekly racing depending on the month. They run TT's, crits, cross, and a hillclimb. There used to be a late-season stage race held by the same folk, but I'm unsure if that's still around. A lot of people used it as a tune-up for cyclocross, which is MASSIVE in this area.
The town itself is a college town, but also run by Nike. There are as many hippies in beat-up Subaru's as there are foreign students in $100k+ cars.
As for the weather, I moved to Corvallis (40 mins north of Eugene) from Montana and thought the rain would be no big deal. In MT, I'd ride do road rides in 10*F weather and even did one MTB ride in -21*F. Man, I was wrong. The coldest I've ever been on a bike was during a gravel ride in the Coast range outside of Corvallis. It was 35*F and drizzling rain/sleet, and I was wearing Castelli's top of the range winter stuff, with a Shower's Pass jacket on top. I lost the ability to do simple math in my head and was slurring my speech when my wife picked me up. The second coldest I've ever been on a bike was during a rainy Coast Gravel Epic race a few years ago. According to my Garmin, it was 42*F (and raining) during the final climb...I was putting out ~300W on a 9% grade climb and shivering uncontrollably. There's something about the humidity here that just sticks to you and cuts through whatever you're wearing, chilling you to the bone. I struggle with the coldness here, even off of the bike. My wife (a native Oregonian) agrees that 10*F in Montana "feels" warmer than 35*F in Oregon.
As for California, every time I've ridden there I've had a "meh" experience. Nice roads but too many cars. It's possible that I've just never been on "the good stuff." I also refuse to live in CA due to the nanny state they maintain (in my opinion).