Here are some things I've heard. I'm looking for an identical monitor to the one you describe and I've also done some research. You might consider the LG 915FT+. The only gripes about it in the tom's hardware review are that in 1280x1024 mode and 1600x1200 mode there is a slight trapezoid problem at the bottom of the screen. Otherwise everything else seems absolutely perfect.
1. Even with the geometry problem, in 1024x768 mode it should be perfect, and having owned another 19" monitor of my own for the past couple years I have never really found use for 1280x1024 in any applications and I basically fit the same category as you, general use and gaming. Here's why (and feel free to disagree)-I ran 1280x1024 once for about a month, and actually got used to it.... but when I had to reinstall windows a month later, I switched back to 1024x768 and realized that this was much more comfortable on my eyes, and that 1280x1024 made everything just too small. Maybe not for a 21", I can't honestly say, but I hate having to squint to look at tiny icons on my 19".
1600x1200 is just not practical. If you increase the resolution, in some games it will not increase the size of menu boxes proportionally to keep up. Lots of 3d games have menus that are overlayed over the main view. If the menus stay the same size (i.e. 100x100 pixels) and you increase the resolution these overlays can become so small that they're unreadable. The patched version of Half-Life has a system called VGUI which increases size of on-screen menus at higher resolutions to make the text on the menus readable, but many 2-3 year old games do not support this. One example is the game Rogue Spear.
Also, the advent of anti-aliasing becoming a default feature on graphics cards now makes running 1600x1200 less economical and even less aesthetic. Running 2x AA in 1024x768 or 4x in 800x600 is much more rewarding than running no AA in 1600x1200 because you get playable framerates and generally better image quality. From personal experience, running 4x 1024x768 almost complete elminates jagged edges (jagged edges are unnoticeable when playing), so if you ask me if I think the games industry is pushing for higher resolutions, I say no. If you think about it, FSAA 4x in 1024x768 resolution is really like running a game in 2048x1536 without FSAA. The reason is simple. FSAA 4x draws the scene 4 times and then collates the image into one. So if we do the math we get:
1024x768x4=3,145,728 texels
2048x1536=3,145,728 texels
One of the very reasons why FSAA was invented was to allow us the freedom to not have to buy monitors and graphics cards that support 2048x1536 resolution at stable refresh rates (after all they aren't cheap!). Also, keep in mind that a monitor you buy today will probably last 7 or 8 years, and during that time, anti-aliasing technology will improve, whereas resolution, unfortunately, will always stay the same. Just look at the matrox parhelia and think about what ATi and especially nVidia will do. Theory suggests that AA processing can be done with just 15-50% of the processing power of current FSAA functions if you target just the jagged edges as opposed to the whole screen, making higher resolutions not only inacessible to many due to high monitor requirements but also requiring more processing power thereby lowering framerate!
Finally, THG claims in their review that it displays black very well. And in my own opinion, that is a very important thing for games. Many games use shadows and I remember I used to play Thief 2 on my old 19" all the time and I couldn't stand how when I lowered the brightness things were just not clear. Things blended together a lot, and color differences were lost. A lot of today's games don't use pitch black at all, even for shadows, so this is really up to you. It may be useless if you play quake3.
2. The LG monitor uses slot mask, a combination of AG and shadow mask, which basically allows a completely flat screen (stays at .24mm all across) but elminates the two horizontal lines that run across the screen in traditional Trinitron setups. It also has excellent text readability, a little better than the P95f. The monitor also has purity zones you can adjust.
3. As for the bargain priced FP955 and PF790, both have a very slight curve to them. The screen itself is completely flat, but the projection is not entirely. Wouldn't bug most people and some may not notice it. The advantage is that these two monitors both run 1600x1200 without distortion whereas the LG, again, has that trapezoid problem at the bottom. Never having tested one of these I don't know how bad it is. Read the THG review to see what I mean.
4. If you visit their website, you'll notice that Sony renamed their g420 to 440, and their slower a420 to 400. But some resellers are still calling it the old name. I've looked at this monitor. Very solid, could definitely be of higher quality than the LG since it can display accurately at much higher resolutions. But it still has the two lines across the screen. Another thing to add. Sony monitors are not that heavy, weighing in at around 52 pounds or 23.6 kg.
5. The viewsonic P95f is really nice for gamers and for watching movies. Some people say that they don't like it because the text isn't as clear as other monitors, but it's got really nice colors. Very diverse, bright, and warm colors. This will be much brighter than the LG, which is a bit dark by some people's standards (for me it seems to be good enough-I had a trinitron and at times it was too bright, and my current 19" is a plain shadow mask, and that's sometimes too dark but very acceptable). This monitor has very minor color convergence distortions at the corners, and some people complain about this, but most like the brightness and color.
This is rather long but I wrote it also to evaluate my own choices and thought process, since I'm also looking for a new monitor. If anyone has a correction then let me know. This may sound odd, but I would have no problem buying a very high quality monitor that only went up to 1152x864. I say this because even after owning a 19" monitor for over 5 years I've never, once, had to go over this resolution. Maybe even 1024x768 is enough. I know people think refresh rates are all the rage, but if you pay more for the monitors that have these high resolutions, and they don't have as many features, why bother? Ask yourself, are you really going to use those resolutions at all? Anyway, you should read some of the other comments people have about slot mask and the LG 915FT+, most are positive.