I've been tweaking my Dell laptop for a day or two and have it quite sweet. Quick spec (WEI)
Core 2 Duo T5550 @ 1.83Ghz (4.8)
2 x 1GB DDR2 333Mhz (4.5)
GM965 Chipset : 965 Express 440MB gfx (3.5) - Not quite sure what ratio of this is shared memory.
Seagate 136GB 7200rpm (5.2)
Vista 32, SP1
On Tuesday it took over two minutes to get from power on to 'workable'. Now it's workable at 39 seconds.
(I waited a while the first time, as there were several services cutting in at various times, whereas now almost all scheduled tasks and delayed start services are disabled.)
Savings of 297MB or a 32% reduction in mem usage from the beginning. Not a bad wee system now, albeit it's just a stopgap Internet and minor task machine.