I can recommend two places where I've enjoyed living for a few years:
Seattle (US)
Great booming city, housing is definitely not on the cheap side but I am sure you can find some good deals with a little bit of research. Very liberal mindset, lot of tech-minded people and great nightlife. Mass transportation is well developed (unlike in most other US cities), the food is awesome (and that's coming from a French expat) and there are lot of cultural and outdoor stuff to do.Brighton (UK)
Brighton is a small town near the Southeastern cost of England. I lived there a few years and enjoyed it a lot. It has that "small town feeling" that you find in a lot of European countries, while being only 20min from London by train. It has attracted quite a lot of tech companies (gaming mostly) in the past few years and also has a large international student population. Nightlife is great, food is average (it's the UK...) and housing is definitely affordable.
Wherever you end up I wish you good luck, I love traveling myself!