If you have a budget of 20k.. it's a no brainer... Get the HTC Touch. It's available for 19k with a 1 GB card and is one of the most amazing looking phones in the current market.
Other alternatives
Dopod 818 Pro (around 20k)
Dopod D600 (around 15k - No WLan)
iMate PDA-L (around 20k)