Yeah, it's weird, because I grew up solidly lower middle class. Blue collar parents, 4 kids (+ child support for 2 more my stepdad was paying), in rented apartments for most of my adolescence. And I guess I've never been able to really escape feeling middle class, even though DW and I are now firmly ensconced in the top 5%. It still boggles my mind, really, that we're in the 95th percentile. And yeah, most of my friends (law school grads) have higher household incomes so that probably has something to do with me still feeling middle class. Besides frequent vacations (budget ones at that), I'm not a conspicuous consumer -- my clothes are almost all Old Navy, my car is a nearly 8 year old Subaru Outback, I don't dine at the finest restaurants (though I do frequent some good ones), etc.
Bottom line is that though I may feel middle class, by virtue of being in the top 5% of income earners we're probably not, though I suppose one might call us "upper middle class" (isn't that what the professional class - doctors, lawyers, engineers, etc -- used to be called?).