Particularly if you run a double up front, don't go super high end on the front dérailleur. Tiagra or 105 should be great. On the rear, I'd say go for 105, and try to score used. 105 is nice and crisp, but far less expensive than Dura Ace or even Ultegra, with minimal performance compromises.
Good call on the thumb shifters.
I like the Dura Ace bar ends. Not too spendy, and bomb proof, though when it comes to urban riding, I've often wished for STI, so I can keep my hands up on the hoods in high traffic situations. I don't know where you could get them cheap. maybe try a WTB ad on craigslist.