You still didn't say which monitor. Samsung has approximately 10 different 24" TFTs.
Input lag is not the same as the response time. The input is the time the monitor needs to react to the user's action. A Samsung 2494HM for example has a
peak input lag of 27 ms. That's ca. 1.5 frames (-> 1000 ms / 60 Hz, etc.) the device sits idle when you move the mouse. Only then it decides it has to do something. That's peak value for DVI input mind you. It's quite okay there and way better with HDMI.
2 ms is not necessarily better than 5 ms because it's an artificial value only reached with digital enhancements. Those enhancements ("overdrive" for example) can cause unwanted effects like a corona effect. The question is how big the effects are.
Really all you need is a 100% stable 16 ms. Just do the math. Is 2 ms plus overdrive better than 5 ms plus a different overdrive? Impossible to say without somparing both monitors.
TN panels are perfectly fine for gamers. This choice will not be the decisive factor in whether or not you'll like your new TFT.
Graphic artists need correct colours because they have to be sure that after calibration the red value ABCDE according to the standard definition looks exactly as it's supposed to look. Gamers can live with a 97% correct approximation by the TFT manufacturer.
Another important point is the interpolation of lower resolutions. There are huge differences from model to model. Ideally you want both interpolation and 1:1 (with a lot of black around it). Most TFTs can't do this though.
As I said, make sure you can return it. Another reason why this is important: The big manufacturers are selling their TFTs in large quantity. They manufacture it in several plants in different countries. You cannot be sure the Samsung display from Malaysia is as good or bad as the on first look identical one from Romania. Plus it's not unusual one TFT model is built with more than one sort of panel, depending on availability. TFTs are like a box of chocolates.
The choice between 16:10 (1920*1200) and 16:9 is not trivial. On the one hand the 16:10 monitor has more vertical space. Very useful for surfing and for games which support it directly. But on the other hand FullHD material has to be interpolated! The picture is either stretched or there's black space around it.
Generally speaking 16:10 monitors are replaced by 16:9 models with FullHD certification.
Which leads to another point. Don't buy a 23"+ TFT without FullHD logo and 1080p support. That's normal nowadays, but there are still older TFTs on the market without these features. Imagine you buy a PS3 in a year, try to watch a BluRay and suddenly find out you can't use it on your new TFT on full resolution. An unnecessary risk.