Would using a smaller screen help me play first-person shooters better?

Doesn't sound right to me...If you have a smaller screen, everything on it is smaller too. A character who may have been 10 pixels tall would be smaller, maybe too small to make out properly, especially given that everything around him would be smaller and less detailed as well.

A larger screen does mean that there's more to keep track of, but your peripheral vision usually takes care of that anyway. 90% of the time you'll be concentrated on a fairly smallish area in the middle of your screen, because that's where you're pointing/looking/walking.

A bigger screen doesn't really mean you'll miss things, either - you'll never be using a monitor that takes up your entire field of vision (if it does, you're probably far too close :P) and human eyes are very good at picking up small movement in the periphery of our range of vision. We notice movement (but not detail) very easily there.

Just like Alex, I don't believe it's a good thing for the following reason's :

• Human sight is large enough to cover a big screen (unless you play in a Cinema or with a 120cm TV)
• If you play on a smaller screen, things are smaller, implies you have to concentrate more (or get closer to your screen) on them and your eyes will get tired much faster. When you're eyes get tired, you loose concentration, etc.
• Aim is also to have fun, and enjoy the immersion in the game, won't be as great on a smaller screen
• The screen won't make you a pgm if you're a noob

As for BC2, I play it but never heard of specific bugs / feature affecting aim. But just the same, this is not what is going to transform someone into a good player.

• If it's about choosing monitor don't bother too much with resolution since it is relative, small area=small targets, Large area=large targets. The thing with lower resolution monitors is that you can play on lower sensitivity(better precision) and with less mouse scrolling get to the end of the screen(cover more area). With that precision and coverage smaller enemies can be faster to hit than scrolling and shooting larger enemy. Basically on smaller resolution you need less physical action which gives you some slight speed advantage(and that is only if you have very good aim and reflexes).

• What matters more is to choose based on monitor quality and type(Plasma,LCD,LED) that fits better to your sight, some monitors have crappy color contrasts and enemy in bushes far away won't be recognized so easily while on other you could spot just a little bit of black color through green bushes.

It also applies to how well monitor displays moves some seem just more natural to eye than others.

Technically that 2 monitor difference are not so important to your eye and you dont even notice them too much, but your brain and reflexes could make a difference. When you are buying monitors you will see bunch of them that look the same (by image quality), but if you play something fast on multiple monitors some will feel much more natural to your sight and grant you better performance(after tweaking brightness, contrast and colors).

• All that said I would go with 22" no matter the battlefield or minesweeper 26" is too much for monitor and 19" is "the box"(4:3) which is outdated and lame for everything else than trying to score better killstreak.