Although it probably won't be the dominant wireless standard, I'm more positive about 802.11a's future than I was a few months ago. Atheros' second generation technology really makes a difference and, in my mind, makes 802.11a a viable alternative for WLAN building - even in home and small office settings.
The improved performance and availability of dual-band, tri-mode products should also help corporate purchasers overcome performance and interoperability fears (once 802.11g is finalized, of course). They'll now be able to standardize on a single client type, build their network with whatever AP type fits their needs, and be able to use 11a's non-interfering channels and 5GHz operating band to escape from tricky 2.4GHz installation problems.
It remains to be seen, however, whether Atheros will continue to be the dominant 802.11a solution provider, and whether the competition has equivalent, or better 11a stuff. The second chance that 11a is getting with tri-mode products will be quickly killed if tri-mode products with inferior 11a performance get shipped by any of the major equipment suppliers. So let's hope WLAN gear manufacturers choose their 11a radio components carefully.
It's also an open question whether Atheros cranks up their marketing machine and starts getting their 2nd gen message across. It's not Atheros' style to be flashy or loud, but in present WLAN product market, they'll need more than whitepapers to be heard over the noise that Broadcom and its partners are making over 11g.
In the meantime, though, if you haven't experienced what Atheros' second generation wireless technology can do, I suggest you get some gear and check it out. You just may see 802.11a in a brand new way!