First off, do some searches in OT, I've posted a bit in similar threads and there's been a good amount of info lately on this topic.
Second, if you live in the U.S., AirsoftExtreme.com has some of the best deals for you. ShortyUSA is OK, but I'd only go to them maybe for accessories (BBs, Gas, batteries, holsters, etc.) and MAYBE a well-researched pistol (like maybe the M11A1 they have on there, I own that gun and it's fine). If you're looking for something less common and maybe want a bigger selection, don't hesitate to go to RedWolfAirsoft.com. They're in Asia, and the shipping is going to cost you, but oftentimes their *cheap* prices + expensive shipping end up being pretty close to the more expensive US prices + cheaper shipping.
Tokyo Marui is the best brand to start out with, hands down. There's some other guns out there that may be acceptable (though I'd never personally chance a Classic Army...I bought a $400 M4A1 and it broke immediately, then my friend bought a MP5A4 and it ALSO broke immediately, so I'm permanently turned off that brand) but you will NEVER go wrong with a Marui. The quality, reliability and cost beats out any other manufacturer I've ever seen (except Systema, but they run usually over $1000). There's more plastic on them than some (Classic Army, ICS, etc.) but the plastic is very high quality and compared to the crap metal the other guns have, it's usually sturdier anyway. I bought an M4A1 from Marui, and it actually weighed more than my Classic Army model. :Q
When getting a pistol, you can chose from Marui, KSC, Western Arms, and a few others and have great results. Marui owns the AEG market, not the pistol market. Western Arms is probably the best you can get...never buy a UHC, stay away from most KWC (except the Desert Eagle, if you like that) and any obscure Taiwanese brands. Non-blowback is probably going to be pretty disappointing for you, too, so try to splurge and get a nice Western Arms or be economic and get a sturdy Marui M9 or maybe a KSC .45.
I'll post some links for you from my bookmarks to check out in a second from places you can trust...
edit for links:
RedWolf - Best asian airsoft shop
Airsoft Extreme - Best US airsoft shop
Arnies Airsoft - British news/reviews/articles... lots of great info
Airsoft Forum - Go here. Great place.
Airsoft players database + info
747 Imports - US shop, a bit more expensive but very trustworthy and has some good deals from time to time
Airsoft Atlanta - I buy almost all of my accessories here, and the occasional pistol. They have a decent selection and great prices on accessories, so always check them out, but be wary of their largely crappy pistol selection and expensive AEGs.
WGC - Another popular asian shop
Airsoft Shop - asian shop good for some obscure stuff, if they have it in stock...