You may find this article of use
http://support.microsoft.com/kb/237740 (it concerns win 2003 server - but the principles hold true)
Ideally you want to minimise the use of the page (or swap) file completely - disk read/writes are MUCH slower than the equivalent RAM operations. If you are using a 64 bit version of Vista (and your mobo supports it) adding more RAM is preferable to tinkering with the pagefile size.
However I agree with Gonz0' s comment that there may be a driver or other issue during the windows start up process. It may be that it is waiting for some process to start and doesn't continue until that process times out. The system logs may give you a clue.
Alternatively, you could regard Vista as the Windows 7 beta - Win 7 is altogether more 'polished' than Vista, and you would probably notice a significant performance improvement.