Switchy - Kinda like Auxo (minus the useless flashy preview) and KillBackground rolled into one + some other nice functions built into the task manager.
Activator - Just amazing. Universal gesture customisation.
Bolt - Replace battery icon in status bar with percentage representation instead.
What do you mean remove default applications? You want to remove Safari and Mail?!?!?! Yeah..I think that would lead to some instability.
If you mean redefine what the default apps are (for like sending an email or opening a URL), then I think there probably is a way (or will be one soon). I haven't mess with that.
Yeah stuff like Safari, Mail, iTunes, App Store are integral to the OS and probably shouldnt be touched. I was talking about specifics like Weather, Stocks, Reminders, Notes, Passbook and Game Center. I've been hiding them in their own folder stored away and untouched but it would be nice to just rid them.