To be fair to Vista, there is less to be gained from the tweaks that have been uncovered so far than was to be gained in XP, but there's still no point having something that you don't use enabled and using up even a couple of MB of RAM, it all adds up.
Yes, & especially moreso, in terms of CPU cycles you save, turning off stuff you just plain do NOT use, or benefit from.
The WHOLE IDEA behind 'tweaking/tuning' is VERY old, & imo, comes from genre like hotrodding cars: taking something you have, & making it ALL THAT MUCH BETTER, w/ out spending if you can avoid it.
Superfetching seems to work very nicely from when I've used Vista so far
Good news that... I am sure they've done their homework @ MS on THAT front especially, since it is a new feature & all that!
- at the moment I'm still mainly using XP though because I can't find a decent free firewall, and the built in one isn't too great... better than XP, but it still isn't nice to use.
Here's one for your tweaks section in the VISTA thread Jim:
Ever consider port filtering in the mean time?
I mention it in a few threads here, & there is GOOD REASON I DO (for cases like this one especially, you w/ no firewall in place, or what you feel is a DECENT one).
I.E. -> It works!
(& is a 'basic firewall' of sorts AND, it works WITH software & hardware firewalls too, & works WELL (layered security in effect)).
It's in the Tcp/IP properties ADVANCED section in 2000/XP/Server 2003!
It allows you to access things just fine outside of your system, via ports you let in/out of it, as you see fit... & is often called "the poor man's firewall"!
Simply because it DOES work as one (albeit primitive, & little control as compared to firewalls that allow on an application level, in/out access, for example).
APK
P.S.=> Take a peek @ your Network Connection in VISTA & see its Tcp/IP networking properties there...
Largely depending if you are on a LAN @ home or work?
WELL, you can turn off things like File & Print sharing (if you're not allowing others to use it, odds are your're not most likely especially if you have a standalone system not on a LAN/WAN) & also dispense w/ using the "Client for Microsoft Networks" as well, if the machine you use is a 'stand-alone' online... & not on a HOME lan for instance.
BOTTOM-LINE/HOW TO DO IT, when & IF you do try it?
Allow in what you feel ports wise on Tcp part (I let in 80/8080 & that's it, sometimes 443) & on the UDP part I usually do ALLOW ALL, but @ times not... & on the IP section, use 16 & 7 (one is the UDP & the other is the TCP portion of Tcp/IP)... apk
some games, probably cod2 and f.e.a.r to start. 
