I really recommend it, my good man. If you have that vague feeling of being a little unhappy where you are then move, it's always worth it, just to see if nothing else.
Since schengen, it's a bit hard for Americans to stay here unless they have someone to sponsor a visa, get married or keep leaving the schengen area every six months (pretty big jaunt). That said, it's totally possible. You just need some cash behind you, or a job set up in advance.
Unless you have some trust fund you plan on draining dry, I wouldn't recommend London, it's ridiculously expensive. If it's the U.K you're after, Edinburgh is a beautiful city and Dublin is insanely fun. Both are pretty ace.
A non-English speaking country is also easy enough to live in. Even the most average city has a collection of ex-pats who can probably help, plus if you can have a job available, it's likely you'll have support until you learn some of the lingo or get a native girlfriend (the recommended choice!).
Totally, totally worth it. I'm way happier here than I was at home.