Zune HD will only come in 16/32. Personally, I hate Archos. Great hardware, and they seem awesome on paper, but their UI is horrible, and you need to pay extra for some codecs that should have been included IMHO.

I'm a huge Zune fan, and have the Zune 80. Interface is great, screen is larger than the iPod classics and the desktop softweare is surprisingly awesome.

Accessories are also well priced, and are on clearance almost everywhere at the moment ($30 for a component output dock + charge + remote).