FWIW, IPS monitors don't typically have much lag. They DO have the lowest response time of the major technologies, so you'll get some ghosting on fast motion. It varies and has been getting better with time and on some designs, though sometimes at the expense of introducing a little lag (same reason/tradeoff as below), seems like typically no more than 2 frames. Look for a good H-IPS display. IPS have far and away the best viewing angles of all the popular LCD technologies. Off-axis viewing tends to just make them look dim rather than exhibiting any color shift. Good LED backlit IPS panels can have amazing contrast, and RGB LED or quality CCFL backlighting can reproduce gamuts well in excess of 100% NTSC. IPS panels tend to be the most expensive of the three major technologies.
VA (PVA, MVA, S-PVA, etc.) tends to have good response time, but getting that requires non-causal overdrive calculations that require the monitor to exhibit "lag" i.e. latency from input to even starting the transition. Hence, they have low ghosting, but the delay may make it intolerable for gaming. Lag is sometimes upwards of 4-6 frames or even more! The latency vs. response time is a major trade-off on VA designs and different panels make the trade-off differently. VA type panels typically have good horizontal viewing angles but mediocre vertical viewing angles, especially from below, where they'll color shift. A common trick when using these (and TN) in arcade games is to mount them upside-down since you're typically viewing from below or straight on but almost never from above. Gamuts can be decent but varies highly with panel design.
TN panels have the most variability. They can exhibit potentially very low response time with low latency. Viewing angles are usually the poorest of the major technologies but this is again highly variable with panel design. Rather than just get dim when viewed off-axis, they tend to rapidly color-shift to the point of being unusable, sometimes as little as 15-30 degress off-axis. Most of these panels are actually only 6-bit color and require tricks such as multi-pixel or time-based dithering to get 8-bits per channel color, and this is objectionable to some, especially on larger displays with lower pixel density (the "dancing pixels" problem). This also limits the panels' effective gamut in many cases, and they're usually paired with low quality backlights due to this (no need for a better one). TN panels tend to be the cheapest.
Of course, any given panel may make different tradeoffs that make it stand out in one way or another from its underlying general technology's typical patterns.
If you're going really big (42" 16:9 or bigger) for some purpose, you might also consider a plasma. They'll burn badly in a typical monitor application, but home-use-only situations tend to not put many hours on them, and they're cheap enough to just throw away and replace when they burn. Even cheap ones usually have contrast ratios rivaling LCDs costing several times more, viewing angles are superb, response time is comparable to a CRT, and you can get them with pretty low lag.
I'm really hoping to see desktop computer sized OLED panels some time soon. Samsung is making 1920x1080 panels at cell-phone sizes now. They're pentile, but at that pixel density you'll never notice.