New machines come preloaded with all sorts of trial-ware (as can be seen by the dozen or so useless icons for the trials). Some of these are in the startup list. There are also several unnecessary services that automatically start up that might be better to set on manual. Ex: DFS Replication, Diagnostic Policy Service, IKE and AuthIP IPsec Keying Modules, IPsec Policy Agent, RtmRm for Distributed Transaction Coordinator, Offline Files, Remote Registry, Tablet PC Input Service, Windows Error Reporting Service. IMO those can be set to manual start. Also, ReadyBoost and Terminal Service are sometimes best to have as a delayed start instead of straight automatic start.

One thing I've heard but I'm not sure I believe is that currently Vista Home Premium uses a % of RAM instead of a specific amount, which when combined with integrated graphics pulling from the RAM for display can cause a machine to be quite sluggish. Again, just something I've heard and don't necessarily believe....I personally thought it simply needed a base of about 512mb.