Skype really, really wants to run at Windows startup. I get it, it wants to be your go-to communications program. What's insufferable is that it gives power users no control over whether to let it run at startup. Even if you dig through the preferences dialogs (which for some reason are largely disabled unless you're logged on to Skype... naughty naughty...) and unflag the "run at windows startup" option, it still runs an "updater" service. Not a "process", mind you. A Windows service, registered in the services pool. Because I really need a process taking up memory 24/7, to check ofr updates at system startup, for a program I haven't actually used for its intended purpose all year. It couldn't possibly be good enough to check for updates only when I actually run the software, that would be such a fragile and inconvenient model.
Funny thing this updater service does, is interfere with startup of other services, like, oh, VirtuaWin, and hey, Microsoft Security Essentials! That really makes me feel great about Skype, that it chokes out my antivirus software.
On that topic, I'm also quite sick of software that replaces the conventional "X" control button with "minimize to tray" behavior. Skype: guilty. Also guilty: Cobian Backup.