Well, you're going to be in a bit of a pickle if you want GAMING and "lite and Slim" - as lite and slim usually denote a LOT LESS power, and GAMING denotes A LOT MORE power. See the dilema?
Also remember, the lighter and smaller it is, the more it costs. Manufacturer's have the market by the balls, and they know how valuable portability is, especially to the business traveller (who has more money to spend on laptops/notebooks). Therefore, think of a PRICE RANGE first. You should know what your parents will say YES to, and what they'll say NO to...
You need to really bear down on your NEEDS, both now and projected (i.e. what do you want to be doing with this machine in 1 year? 2? etc.) Sagers are great for gaming, as I'm sure you'll garner from these forums; however, they are HORRIBLE for "lite and Slim" - they are the antithesis of those terms, actually!
Something in the middle (can game SOME games, just not BF1942 or Unreal2) but has decent battery life (i.e. 2+ hours) may fit your bill. In that case, look to a Centrino - or centrino-like laptop. Couple points: CENTRINO is NOT the processor (Pentium-M) it is a combination of 3 things (CPU+intel's wifi+chipset). Many notebooks out there have the Pentium-M (cpu) and the Chipset, but use their own wifi, thus are unable to claim "Centrino" - it's a marketing scam by Intel.
Anyway, the Pentium-M chips are GREAT at battery life, etc. so many highly portable (lite and slim) devices use them; it's also not bad at gaming. Not the best or even the "goodest" but it's OK. Check around for "Pentium-M" loaded models, and get back with us.