Flash sites ftl.(yeah other flash sites work fine
)
Seriously, I would never make a flash-only website. Also do note that flash doesn't really work well on PDA's/Mobiles/etc.
I guess you could create multiple sites for different platforms. But it's probably easier to make one site viewable for every platform.
This in itself is quite hard to accomplish. Since you'd have to keep in mind that people use IE/Firefox/Opera/etc. and all of them render sites differently. It can be very hard work to make a site compatible with every possible browser/OS combination. So like, if you're outsourcing the creation of your website be sure that they deliver something which has this compatibility.
Anyway, imho other than looks it's waaaaay more important that your site is easy to visit- and navigate through.
Agreed with all of the above. Especially the last bit.