It’s very simple to decide: For office work(more so if you are in the IT business) go for a branded make. For all other uses, a good assembled PC is more than enough.
Just ensure that your supplier gets you an original Intel mother board and at least an OEM license for Win2K/XP whichever you choose. The most optimum configuration should look like this;
Genuine Intel motherboard
128MB RAM(make it 256 for high end graphic applications). Check for future incremental expansion capacity. DDR RAM is the best.
40GB HD minimum. If you regularly download huge files, then it’s better to have 2 HDs. Use one the store all your data and reserve the bootable drive exclusively for applications.
Instead of a CDROM drive, try to fit in a CD-RW. Blank CDs are very cheap(at the moment they retail for less than 20 bucks) and u can use then to backup sensitive data.
15’ Monitor a must. 17’ is the best fit for all applications except the most graphic intensive ones. Depends on your budget though. I have found the LG monitor to be a good buy.
Mouse - Definitely the optical variety. Worth the extra bucks. Scroll mouse.not for me.
Any decent cabinet with plenty of space for dissipating the heat generated.
Multimedia - Unless you want to use the PC as a home theatre, don’t go for fancy stuff. Simple 2 speaker system is adequate to listen to music and watch movies(don’t advice watching movies on the PC unless you want to visit your optician more often).
Modem - 56K external. Hate internal modems. If your cable provider offers u internet services, go for it. Mush faster and a whole lot cheaper. Check out the BSNL internet connectivity offering though. Looks cheaper than other providers.
Amongst the branded ones, I would go for IBM or Dell.