You can get a decent TFT to handle the job but be prepared to part with a hefty wad of mula.
Most 18-inch TFT's support a max res of 1280x1024- you'll be hard pressed to get 1600x1200.
More important than res for a TFT is candelas, contrast ratio and response time. If you can track down a model with about 350 candelas, a 400:1 contrast ratio and a 20ms response time you'll have no trouble playing first person shooters.
Senior Reviews Writer