Introductions - new socal rider needing advice

i used to ride from time to time until my bike was stolen and i never got around to replacing it until now when i was suddenly struck with a passion for biking. but the first issue of course, is the buying of the bike. ive been to a few websites i got from this site, and the local store and am amazed at the prices 500 - 5,000$, i didnt know bikes could cost that much. so i was wondering, my wise biking bretheren if there was some not so terribly expensive website or perhaps even specific model that was mountain/streetish, and more geared towards the streetish?

That's a loaded question. Mountain/streetish sounds like a C'dale Bad Boy. Streetish could mean anything from fixie to cruiser. Try deciding what kind of riding you'll be doing the most (mountain xc, downhill, urban) and what elements are important (speed vs. utility, light weight vs. bomb proof). Your answers should lead you towards a bike type. Or you could just buy a cyclocross bike. More streetish than mountain, more roadie than mountain, lighter than a mtb, heavier than a roadie.

hehehe i know it was a pretty general question but i really know nothing at all about bikes. so to specify on the lovely neat choices youve provided... as far as riding, mainly in urban places, downhill, uphill, flat, where ever in the city, but i also want it just to be able to mountainous places.. trails, hills.. no 50 foot drops or anything like that. definitely speed over utility, definitely light weight over bombs. i looked at the C'dale, dayum. i was thinking no more than $350... that things a bit outside of my pricerange. also, is there somewhere where i can get a breakdown of the different bike types instead of asking a million questions?

Go to www.sheldonbrown.com and start reading the articles. You will learn more about bikes and cycling then most people ever want to know. And well written.