i've used several laptops, and am a big fan of IBM's sheer usability, especially the high-end models (T42 is a personal favorite). Toshiba comes next, and Dell and compaq round up the top league.
For you Mansi, i'd suggest following criterian:
1. Light-weight: At 70k, you should look at ultra-portables weighing in 1.200-1.800 kg range), but they must have inbuilt DVD/CDRW drive (never sacrifice internal drive for super-ultra-portability, as I did recently with my new BenQ 6000 and am ruing this :( )
2. 12" screen: People make too much of laptop screen sizes..I think 14" and 15" are totally useless. Most ultraports come with 12" screens, you just need to figure out the screen layout and ensure key sizes are not compromised (an issue with some companies' ultraports)
3. Centrino: Simply stated, it means is that in about a year's time, you could simply take your ultraport out, sit on a cafe chair or an airport lounge sofa or a railway station bench ;-) and get connected to Internet wirelessly! Don't run after GigaHertz speeds of processor, older centrinos are a steal provided they come at a massive discount!
4. Battery backup: The manual should talk of a 4-hour runtime at least...though you get all-day portables today in the higher-ends
5. Brands: In order of my preference: IBM, Toshiba, Dell, Compaq, Samsung/LG, Acer, ACI, Assembled laptop, Korean assembled laptop, home made laptop
Hmm... I think that should be it. Happy Hunting!