Open source tweaking app Vista Services Optimizer adds Windows 7 love in v1.2
It also allows you to create different profiles, provides a one-touch gaming mode, can take automatic service state snapshots, and offers painless recovery of Windows default settings. Version 1.2 is also Windows 7 friendly (64-bit builds included).
VSO is also a nice app for casual tweakers -- you don't have to know what each Windows service does or whether or not you can do without it. Just answer the (mostly) plain English questions VSO asks, and it takes care of making the necessary changes to your services. The built-in Rescue Center makes undoing changes totally painless.
Vista Services Optimizer is offered both with an installer and as a portable utility (host machine must have .Net 3.5 installed). Downloads from the developer's site can be a bit slow, but you can also find VSO over at Softpedia.