city vs. city threads are HIGHLY frowned on in this forum, but since you're new it's ok--I certainly wouldn't start one outside of MW. but if you like that and the non-stop trollfest it invites, head on over to that other skyscraper site whose name escapes me now.
anyways, i would say tempe has the best downtown now--it's interesting and has height, has parts existing before World War 2, and it's very walkable. i'm not big on malls or clubs and generally dislike Scottsdale, so I'm biased of course. downtown scottsdale is also the largest of all three, but there doesn't seem to be much cohesiveness between the various spread out districts. tempe and phoenix also have better transit service and always will.
but downtown phoenix is still the capitol, and will always have that edge over the other cities. our buildings are generally older. urban form is back on track. despite the city's best efforts to kill it, our art scene runs circles around scottsdale's and tempe's. the office market here is too cool, and I'd rather have our "8 buildings" and vacant lots than the sprawling auto clusterfuck of north scottsdale that provides just as much raw space. here, with all the vacant lots and height, it's almost a blank slate to grow and prosper and much more fun to watch--whether for the better (towers over parking lots) or worse (Madison Square Garden). the other cities, perhaps too filled up even--tempe's done, and scottsdale never had any shred of history.
think as soon as the residences and stupid ASU students normalize, Phoenix will be picking up mass amounts of steam as all the 7 AM - 3 PM businesses gradually start to stay open later and later.
coming in from the 10, you can now see 44 Monroe's crane peaking up above the skyline as well as all the other activity going on just ringing the core--it's amazing. late 2007 to mid 2008 will be the year of the crane downtown--let's review the stuff that should still have a decent sized one by then:
44 Monroe perhaps, the Criminal Court Tower, the journalism school, the student housing, the convention center, the hotel probably, the MAG Tower, Wood Partners, Omega, CityScape, Central Park East, are all good candidates. Jet and Copper Pointe might as well, in addition to I'm sure a few sketchy projects we haven't heard of or went stale and the bioscience campus stuff.
granted, hopes don't make a downtown, and most people don't care about a criminal court tower. but by sheer size of just the guaranteed stuff--ASU, MAG/CCT, the convention center, the hotel, hospital(s), and light rail, we should do alright.
and to think, our "bubble" is deflating. if we have another 2005/6 past 2009, Phoenix, as well as Tempe and Scottsdale, will be absolutely insane.
either way, I'm happy to be in the metro. we should be fortunate that we create as many jobs a year as 45 states.