The precision that the gaming mice offer over the regular mice for Dell or HP (that cost <400 rupees) is debatable. I have been using logitech G500 for 3 years. Before that I had used another Logitech 8 button mouse that cost well over 5K that time. My G500 conked off a year ago. I have been gaming with a regular Dell mouse that I bought for 300 bucks. Its been serving me well.
The above would depend on several things such as what kind of games you're playing and how "good" (meaning skilled) you are at them. As someone who has been playing FPS since 1994, I personally believe a good mouse (and decent pad) are absolutely critical if you're a serious gamer. If you're a casual gamer then a Rs.400 mouse is just fine.
If two equally skilled players are playing a competitive FPS (say CS or Quake Live for eg) where one is using a Rs.400 mouse and another is using a Razer Deathadder (or equivalent), their performance (read KDR) will not be the same. The one with the better mouse will perform much better. And by "much" I mean the difference will be obvious and noticeable.
Plus, its not just precision, its lift off distance as well. Pick your Rs.400 mouse half an inch off your mouse pad and see what happens to your tracking. Now try that with a quality high end mouse and you will see the difference. Similarly, make very rapid left-right movements with a cheap mouse and then compare that to a quality mouse. The tracking/response difference is very significant IMO.
Precision wise, if you see, the pro gamers worldwide play with the normal mouse with a very few exceptions. On paper, high precision laser might sound appealing, but as soon as you start going above 1200 dpi, the ROI start decreasing sharply.
I would disagree, at least as far as FPS go. All the pros I know of use high end mice and pads - no exceptions. You HAVE to because its an edge you simply cannot afford to lose at that level. If you know any Pro gamers who use normal mice, I would like to know who they are.
As for your mentioning "laser" mice - from what I know, laser mice are in no way superior to high end optical mice. Two reasons I say this -
1) Most of the "pro" gamers that post their configs seem to be using high quality Optical mice. FYI, here's a list of mice QL pro gamers use -
http://pastebin.com/G8qUVjp3
2) Fatality, a "pro" gamer, had a Laser mouse named after him (Creative Fatal1ty Professional Series Laser Gaming) but uses an optical mouse himself. If that is not telling I don't know what is.