Iv got a 23" phillips full hd monitor and it works great with my xbox and pc
I just bought a 32" Samsung LED and it is awesome.
Just remember you will need about 1m viewing distance. Obviously being a huge monitor, the pixels are spread a bit more so not as crystal clear up close as a smaller monitor, but awesome nevertheless.
And as mentioned, 24" monitors are crazy expensive, you may as well get a 32" TV.
I've got a 23.7" Samsung think it's 2494HS or something.
It has an HDMI port whcih makes it easy for my PS3 and VGA for my laptop.
I think they are around R1100 now.