Morning guys!
Sorry for the late response, over here in Perth we are on a different time zone
What are you gaining by moving to a higher resolution...
Its a debate similar to a minefield. Ask a home cinema guy if you can tell the difference between 720p and 1080p... You will get all sorts of answers and a religion like debate.
Obviously with a higher resolution you will see more detail. But your monitor is also larger, so you will likely have it a bit further away.
When I game I have my 18.5" LCD really close. I have put it on a few books and move it really close. When I watch a movie I push it back again.
I believe that jaggies are still around, even on a Full HD screen. Thats why I love 4x AA, it really lifts the IQ.
The reason I chose a 720p screen (mine has 1366 x 768) is because it is the "fastest" resolution in modern LCDs and I get more value out of my hardware. I have a basic Radeon 5750, but I can play games at settings where a Full HD screen owner would need a much stronger graphics card.
Another reason I chose this resolution is because I do play older games (like point and click adventures) and most of them run at 1024 x 768. As long as you turn on GPU scaling in your driver you can play letterboxed (black bars on the side just like on a widescreen TV when you watch a old movie).
Anyway thats just some reasons why I chose a lower resolution screen. In the end it is a personal choice and there is no right answer...
EDIT:
Now I wasn't such a gamer, I would buy a Full HD screen hands down. Simply because they don't cost much and you get a massive screen.
So for me gaming performance (and value) is the only reason why I chose this 18.5" screen.