I am now at a crossroad to reinstall a 64-bit Windows OS -- just for installing the newest VMware VSphere client.
That's not completely true: the problem is XP, not the 32bit architecture. I was in the same situation, and my host is Atom based (no VT-d, no 64bit VMs): right now I'm running vSphere Client 5.1 (786111) on a Win7 (32bit) VM to connect to ESXi 5.1.0 (1117900).
Not a web client, but better than nothin' :)