While this doesn't qualify as a registry hack, it does require some examination and possible registry changes.  In the absence of a registry clean-up utility, I would use the rudimentary tool of regedit. 

Run regedit and then use the find facility to find every instance of 'runonce'.  As it turns out, your really interested in the 'Run' keys that will be immediately preceding the runonce instances. 

Take a look at the entries associated with the Run keys.  You'll probably recognize many of the entries that you know get launch at startup.  Most likely, there will be a bunch of entries that you don't recognize and don't need running at startup.  Select each entry that can go away and delete it.  It's very possible that there are some nasty things running at startup that shouldn't even be on your machine.

I've seen upwards of 30-40 things running at startup when only half that many are really necessary.  If you're also experiencing a lot of pop-up ads, then it's probably a good bet that you've got some things running at startup that are designed to deliver pop-ups.

I've seen some entries that watch for removal and put themselves back in, over and over again.  To get rid of those you need to run regedit in while in safe mode. 

Once you've cleaned up the run entries to just the minimum items, then you should have a quicker startup...

Hope this helps.