Hey guys im a complete noob when it comes to choosing a monitor so can ya'll help me find a great GAMING monitor for around $150-200.

Here are my PC specs:

Videocard: (2)
ASUS EAH4850/HTDI/512M Radeon HD 4850 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card
http://www.newegg.com/Product/Prod [...] 6814121253

Motherboard:
GIGABYTE GA-X48-DS4 LGA 775 Intel X48 ATX Intel Motherboard
http://www.newegg.com/Product/Prod [...] GA-X48-DS4

CPU:
Intel Core 2 Duo E8500 Wolfdale 3.16GHz 6MB L2 Cache LGA 775 65W Dual-Core Processor
http://www.newegg.com/Product/Prod [...] 6819115036

Memory:
Patriot Extreme Performance 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory
http://www.newegg.com/Product/Prod [...] 6820220269

Operating System:
Microsoft Windows Vista Home Premium SP1 64-bit English for System Builders 1pk DSP OEI DVD - OEM
http://www.newegg.com/Product/Prod [...] 6832116488

Hard Drive:
Western Digital Caviar SE16 WD7500AAKS 750GB 7200 RPM 16MB Cache SATA 3.0Gb/s Hard Drive - OEM
http://www.newegg.com/Product/Prod [...] 6822136131

Optical Drive:
SAMSUNG Black 22X DVD+R 22X DVD-R 16X DVD-ROM 2MB Cache SATA 22X DVD±R DVD Burner with LightScribe - OEM
http://www.newegg.com/Product/Prod [...] 6827151173

CPU Cooler:
XIGMATEK HDT-S1283 120mm Rifle CPU Cooler
http://www.newegg.com/Product/Prod [...] U%2bCooler

PSU:
CORSAIR CMPSU-750TX 750W ATX12V / EPS12V Power Supply 100 - 240 V UL, CE, CB, TUV, FCC, CCC
http://www.newegg.com/Product/Prod [...] 6817139006

Case:
LIAN LI PC-65B Black Aluminum ATX Mid Tower Computer Case
http://www.newegg.com/Product/Prod [...] 6811112040

Keyboard / Mouse
Microsoft 65X-00024 Black 104 Normal Keys 8 Function Keys USB Wireless Standard Optical Desktop 700 Mouse Included
http://www.newegg.com/Product/Prod [...] 6823109022

Remember keep price around 150-200 but good quality GAMING monitor.

Most popular name brand LCD monitors are good for gaming. Go with a 20 or 22 inch monitor if you wanna keep it in that price range.

Does response time make a big difference? From 5 ms to 2 ms?

Anyways at your price range the best you can hope for is a 19" LCD.

if you are going for a crossfire setup with two video cards you need to be using a 24" lcd or bigger which is more than your price range. the reason being that crossfire and sli is only worth using if you are at very high resolution 1920x1200 or higher, otherwise the performance gain from dual video cards is minimal. if you just want a 22" moniter i recommend using just one 4850 and picking up a samsung 22" i have one of those they are great, the resolution was 1680x1050. the moniter i'd recommend for the setup you listed is the hanns g aka hannspree 28"(27.5" viewable) it's about 500$ so it's far beyond your budget, but i have one of them and i can tell you it is the best money i have ever spent on anything computer related. also be aware that many lcds will have stuck pixels you will have to "massage" on a bit to get them working(google for info). on the response time, lower is better, especially for gaming, if the response is too high aka slow, you will have "ghosting" in games. btw that is a nicely spec'ed system, it is almost exactly what i would get if i were building a new one right now(i'd get e8400 instead of e8500, it's 30$ or 15% cheaper and only 5% lower clock, 3ghz vs 3.16, and it will overclock great with that motherboard).