I have also found that my scroll will load all sorts of stuff on boot and until I terminate the tasks the device runs sluggish.
I have been using "Advanced Task Killer" as Veng. I have found it to be quite a good program.
After reading this thread I gave "android task manager" a try and it looks like a more refined and finished product and it has a very nice "system info" report.
However one nice feature of "Advanced Task Killer" that does not seem to be in "android task manager" is once you have selected the apps to kill (and there is a tick next to it) it remebers these. So next time you reboot your phone (or start a process manyally) the tasks you have previously seleted to kill are already selected.
I have also noticed that "android task manager" auto-starts even if you select the setting "start automatically when you restart your smart phone"
I am also going to give super manager a go