I've been looking at a USPc in .45, but I don't know if it would be pointless or not.  I've got an Ed Brown Kobra Carry.  I want a nice German autopistol and think that the HKs are top notch, but maybe I should hold out for something else?

Well, its a damn fine firearm.  Familiar controlls and grip angle will be a plus.  I have 1911's and USP's, and I've never considered purchasing one one similar sizes "pointless".  They're similar, but very very different animals.  

Only thing I'd advise is that you hold out for the compact Tactical.  Its gonna be a sweet little blaster.  Or, check out the fullsize.   You already have a firearm you can conceal, so checking out the USPF wouldn't be a bad idea.  Comparing ease of concealability between a USP of any size and a 1911 will always lead you back to the same conclusion...the 1911 is easier to conceal. I highly recommend the tactical line whether it be a fullsize or compact model.  Match trigger goes a long way for the fullsize (not available on the CT), as does the accuracy of the Oring barrel.  And you never know when a threaded barrel might come in handy.  

To answer the question in your sig line...you already know what Jack Bauer would do... the same thing hes been doing since season 3.  Carrying a USP compact.  Need I say more?

I alternate three times a week between my Colt Commander and my P2K.  They are easy to use and I use the same hold for both.  For me it's weak hand finger on the trigger guard, weak hand tight 4 fingers under the trigger guard, Strong thumb locked under the weak hand.  Both thumbs pointing toward target.