Samsung 15" lcd. Had a 17" Dell LCD but I couldn't read the print on most web pages comfortably from 5-6 feet. Lots of eye strain, so I switched back to the 15". Also, the power consumption of the Dell 17" was at least double that of my old Samsung 15", it had 4 backlights instead of two in the Samsung. Lastly, I game at 1024x768 with my Nvidia IGP, so that's native res on a 15".
The only upgrade I might make is to a conventional 19", but right now I like the size of the 15" and I very much appreciate the 15 watt power consumption.