Personnaly I prefer Samsung. I have a 24" 245BW monitor.Dell Monitor's are super nice as well, but more expensive.
Another thing you have to consider is the bigger the monitors the more lag you will have and this is true especially for gaming which is a bad thing.
Before buying check these things:TN, PVA/MVA, and IPS
TN = considered the hardcore gaming monitor, lowest color accuracy, fastest response time/input lag due to low need of processing. Worst viewing angles.
PVA/MVA = Highest contrast ratio, decent input lag/response time. Ghosting is an issue, blacks crush as well. If you Don't know what black crushing is, it's basically details in darker areas merging together into a giant block, aka, black crush.
IPS= Best in terms of color accuracy, faster response time than PVA/MVA, but not as fast as tn. Most expensive.