http://wiki.pomona.edu/bin/view/FAQ/WinXPProcesses
For those (like me), who find it difficult to keep all the Windows XP processes straight, here's a good list on the Pomona College website. It gives a brief description and its color coded which is nice. Its not all inclusive but thre's a link where you might find a process not on the list.
Be sure to read the process description. You may find some good tips and examples of 'look-a-likes.
BleepingComputer.com -> Startup Programs Database is a good reference for auto started applications:
Yes,they both have their purposes.
You won't believe this real-time utility that DennisD has been hiding somewhere.
It sure would have come in handy when I was optimizing start-up and services and checking out processes.
You can do everything at one time without going to other sites or anything.
Try it and you won't get rid of it. It definitely is a keeper.
What's Running 2.2
===================
What's Running is a tool to help you explore what is actually running on
your computer. By giving you a detailed look into Processes, Services, Drivers,
IP-connections etc you can get a more detailed understanding of what's going on
in your computer.
What's Running is a product that gives you an inside look into your Windows 2000/XP/2003 system.
Thanks Dennis,
davey
Aw davey. You've got me embarrassed here. 
I have procexp.exe installed. I know I could install whatsrunning and compare it to procexp.exe myself, but if I didn't control certain impulses, I would have every utility in the world on my compiter. And then be scratching my head wondering why my PC was running so slow.
Even so, I would still be interested in hearing opinions contrasting the two.