We tip in bars (and casinos, of course), too, but good tips are usually balanced by free drinks, top shelf liquor, extra flirting from the waitress ;-), etc.
EDIT: I don't tip delivery people, though, especially the pizza guy. I did tip, however, before they started charging delivery fees.
EDIT2: And I hate tipping the bell service, doorman, etc. at hotels, but I do it anyway.