Dual for gaming is being seriously under-rated.  You stick all of your messenging shit on the second display so you can keep track of things without tabbing in and out every time you recieve a message.

Thanks for all the responses. I think I might go with the dual screen but not necessarily for gaming. I will try to get at least 22" and play games on single screen while using the second for things like chatting with friends on TS for example or xfire and the dual screen to expand my future blogging ideas. I plan on expanding on blogging by going video and dual screen may come in handy with all the software and sites I'll be using.

For the person from UK who didn't think I could find a monitor for $350. I am not sure if this is a great monitor but it is big and for around that price:

Hanns·G HG-281DPB Black 28" 3ms Widescreen LCD HDMI Monitor - $299.00

Go with dual.. period. I play games and it is handy as anything to be playing and have reference material (ie.. hints, manuals, notes etc) on the other monitor to reference whilst playing. It is extremely convienient in all apsects of use. You'll thank yourself for doing it!

2 is good, 3 is better - but I have 5 here with 4 computers...

I do a lot of work and I do not mean skinning - thats a hobby. I mean work... pays to have what I have to do what I need to do.

But dual for one system is very good if setup correctly.

I have a dual 22" setup and find the second monitor very useful for referencing materials when/while working in full-screen on the first... saves a lot of time with window minimising/maximising.

I don't play games that much, but a second monitor is great for keeping an eye TV (news, sport, etc) while doing something else... saves having to go into the loungeroom to see items of interest, sometimes missing stuff cos I'm too slow getting there.

As for playing games, I would imagine the game content itself would be best on just the one monitor, with related and non-related stuff on the other... as has already been said, the monitor frames would likely be a distraction.  While going from one screen to the other may be instantaneous, the frame could well be the difference between shooting an opponent's spaceship (whatever) and not.

Right. If you use it for chat, or your minimap, or whatever, the second screen can be quite useful. But I think I would prefer a better sound system over an extra monitor. Hearing the gunshot to the right, turning and taking the kill is priceless.