The main thing to keep in mind while buying a PC is its use. Predict the current use and the future use in next one year to extend the usability. If money is not a constraint then I would suggest a system with dual core processor. At least 512 MB of RAM, 1-2 GB preferable. At least 80 GB of Hard Disk Space. A good graphics card with 128 MB of RAM will support games and Video. Choose a dual layer DVD writer for your machine. If you need a PC just for basic office functionality and internet browsing then go for any good branded entry level PC. A branded entry level computer would offset your budget by just 18-20,000 Rs in India. Dual Core by about 25-28,000 Rs.
"Buy Once Buy The Best".