Also note your ability to install the 64 bit OS depends on what processor you have, for example I have the T2130 in my Inspiron 6400/E1505 and so cannot install a 64 bit OS. Edit: didn't read properly, your processor is fine.
I think if you have the T7200, T7400 or T7600 you should be good to go. If you have not already done so you can install 4 Gb of memory (2×2 Gb) and 3.24 Gb - 3.3 Gb of this will be usable.
If you can find the video drivers from the vendors websites and if the drivers from the list above work then it should be fine. (The touchpad driver isn't so important, nice to have but not critical, the 32 bit version may work). Again there is next to no advantage of running xp x64 over xp x86 on this system.
Edit: Video You could try following this guys instructions.
All right... I think I have all the drivers I need for full functionality in Win7 x64 now.
downloads.dell.com/.../R141208.EXE - Synaptics x64 driver got the tap-click disabled and scroll bars working.
ftp.dell.com/.../R168331.EXE - Ricoh card reader driver that everyone recommends above got rid of the last of the question marks I had in devmgmt.msc (Device Manager)...
ftp.dell.com/.../Ricoh_R5C833_A00_R240788.exe 'looks' newer, but unless I have a problem reading or writing from/to SDHC cards (which is about the only format I use in it), I'll hold off on that.
I wanted x64 mainly so I can run 64-bit versions of some programs, not because I think it's going to make my notebook run any better. I had a new blank 500GB hard drive to try it on (because Dell Support Center has popped up a couple warnings that the WD 120GB it came with is failing), so I installed MediaDirect 3 on it (I couldn't get a copy of MediaDirect 2 ANYwhere) in an extended partition, Win7 x64, the rest of MediaDirect, the Dell NSS, chipset and drivers, and everything is (apparently) working. 🙂
Now I can stop and make a restore image or 2 with Clonezilla, then figure out which flavor of x64 Linux to dual boot in the 180GB I left unallocated.
I'm probably going to pull the keyboard and swap in an Atheros-based Ubiquity SR-71E because the PCI\VEN_14E4&DEV_4328 device wasn't fully-supported in Linux the last time I checked with a Live CD (WiFi light wouldn't light and the Dell 1500 card was not detected with lshw nor lspci).
All in all, this thread was very useful, in my honest opinion.