Sane configuration options for a WinXP laptop 8.1 install?

In an attempt to save myself some time, I thought I ask The Community
if anyone has guidance here.

HW:  Intel PM (very likely to be upgraded to an AMD Turion when the
proper HW becomes available) w/ 2GB of RAM (shortly to be 4GB) and a
5400rpm 100GB HD (will be dual 7200rpm 160GB HD's as soon as they
become available)

OS:  The laptop in question is running the latest WinXP service pack
and patches.  When the CPU and HD upgrades mentioned above happen, I
will probably start running dual boot FC5 + 64b Windows.

Possible optional HW: external "box of HDs" for doing and/or
modelling stuff that can't be using only the internal ones.

I want to get as much performance as I can out of the HW + OS.

Anyone want to take a stab at what the config files and options
should be for best performance under most circumstances?

This is intended to be a portable development platform, so opinions
as to which contrib modules are worth/not worth installing is also appreciated.

TiA,
Ron