Michelin Super Sport. I've just put 30KM(19mi) on my rears. I drive fast. Can't believe the stick and wear rate.

My car came with new Bridgestone Potenza S-04 Pole Position and they are pretty darn good. Done a lot of hard twisties and the stick like a tick on a dog! I am in socal so do not have to worry about rain too much - but they have been good so far.
Not that expensive either (in 17" sizes). Thy look good too and have a wide edge to keep the wheels away from kerbs.

Unless you want "Ultra Hi-perf" Michelin AS 3

If highest street performance on the dry is what you want, then these:
http://www.tirerack.com/tires/types/extremeperf.jsp

I had the Conti DWS on my wife's car, the tread squirms way too much for my liking, and dry handling.

A bit like "which oil?" but here is a different perspective:
I cringe when people say 'I live in a dry area so wet road grip isn't a priority'. I live in an ultra dry area but when it rains the accumulated oil/diesel+water is treacherously slick ,particularly on asphalt. If you use ultra high performance summer tires in such conditions - it will feel like you are on slicks. The Tire Rack test videos show the wet road test - it is just water -no oily/diesel residue. If you watch/compare the best wet road grip tires performance in the dry ,there is very little sacrifice . But the other way round ,the penalty can be severe.
The 'Spider Charts' at Tire Rack are useful to figure out the trade-offs:
http://www.tirerack.com/tires/tests/spiderChart.jsp?ttid=194
For example, Yokohama had a slight edge in Dry but was a dud in the Wet. Pirelli P Zero was almost as good, in the Dry - but way,way better in Wet. YEMV
Fast+wet is when you'll need the best compromise, not fast+dry (for normal road driving)

Back many years ago, just as it started to rain, I was trying to negotiate a reverse camber (slopes away from the inside of the curve) ninety degree turn at only 20 MPH and found myself sliding towards another car and the front end of my VW type 4 folded up in front of my eyes. After incident analysis said that the tires were at fault. I had bought the car less than a week before and the tires looked good. Picked up the car a day later at night and didn't reinspect. Dealer had switched tires. Yes the type and condition of tires makes a difference and a curve is where oil get deposited over the weeks between rains.

Also go look at the stopping distances of varying tread depths in a good rain. The difference between a new tire and one worn down to 2/32 (legal limit in many states) in a test on a water soaked surface was an almost doubling of stopping distance! 4/32 deep tires took about 50% longer to stop than new tires.

New - 195 feet

4/32 - 290 feet

2/32 - 378 feet

Even more startling to me is that on a 2/32 tire, in stopping tests in the wet from 70MPH, the new tire would have stopped the car where the worn tire would only have slowed the car to 55MPH!!!! 4/32 would only have slowed the car to 45!!!!

Wet grip/worn tire best=Michelin Premier All Season
 

Mike raises an interesting point about deteriorating wet road grip with worn tires. Such tires would grip just fine in the dry.
New tread groove profile in the Micheline Premier A/S reduces the rate of wet-grip deterioration with tread wear. The "Evergrip" design is not offered in M.Pilot-Sport unfortunately.
Tests Reveal the Michelin Premier A/S Tire Doesn

I had these tire on my 18" carrera lights and I liked them alot, till they aged. They started getting really noisy. It was a pain to drive like that.

i have Michelin AS-3's on our Targa and they are noisy as hell on grooved concrete freeways

Interesting thread since I recently bought a Boxster and it will need new tires in the Spring. I've had some experience with the Goodyear F1s on my SAAB Viggen and I would never have considered them for my Boxster. I was happy with them for the first few months but as they wear they get loud...really loud. They ride much harsher than the Michelins (PS2s or PSSs which I currently have one the Viggen), and lose their wet performance capabilities very quickly and don't handle that well. Perhaps they'll do better on the Boxster they did on my Viggen but I'm not taking that chance!

Car came with Sumitomo HTR ZIII - I put 24k miles on the rears before I replaced. Probably 5k more than I should have. Fronts still good

All new tires need break in but what one also needs to be aware of is going from little tread (worn tires) to full tread.
There is a big handling difference. The worn tires performed much more like slicks as far as minimal squirm. The new tires, with full tread, have a bit more squirm factor because of full tread. So new tires, same tire, will perform different verses Worn

PS2 vs. A/S3
 

My situation is very similar to the OP's: 2004 Boxster, daily driver, live in Central Texas, so very hot summers; not a lot of rain but as a result, when it does rain, the roads can get very slick; snow once every few years, a few freezing days each year, otherwise 40's are common in the winter.

I bought the car with Michelin Pilot Sport PS2s on it, have gone with the same each time I've had to replace them, and have been very happy with them other than having to shell out a grand each time. It is that time again, and I'm torn between the PS2 or the Michelin A/S 3. The A/S 3's are 2/3 the cost of the PS2s, have 2x the tread life, and will presumably be better in the occasional cold/wet (not that I've had any real complaint with the PS2s in the cold/wet). So, how much would I be giving up in terms of dry performance, ride quality, noise, etc.? Anyone had experience with both of these?