MY SYSTEM CONFIGURATION IS AS FOLLOWS

Intel Pentium D processor 2.33Ghz
512MB DDR2 RAM
Intel D102GGC2 Motherboard
Seagate 80GB SATA Hard Drive
ATI Radion Express Graphics

for this configuration which version of linux is best. As I wass thiking of Instaling OpenSUSE.
Which one should I Install Either the 32bit or 64bit version.
please help

Is the pentium D a 64 bit processor? Sorry I'm a longtime AMD user so I'm not too familar with the intel cpus-anyway 64 bit versions can function well on the appropriate cpu but since it's a relatively new technology there are some growing pains i.e some apps don't do well with 64 bit. (You can run a 32 bit version on a 64bit cpu)
OpenSuse is a good distro you might also take a look at fedora-pretty good community at their forums too. BTW ati (your gpu) is getting better support but IMO is not as well supported as nvidia in linux.