Comment One Thing: Win32 (Score 1) 865
Transparent Win32 Execution, by default on install.
Take the grandma scenario. She wants Word, A photo applicaion and quickbooks. No it doesn't matter that there are alternatives, she's got a copy from 2002 that she uses with backups, and she doesn't care to learn a new product. If the average Joe PC can pop the CD in and double click the CD (autorun) and the setup pops right up (wine) without having to go too a command line you have immediately expanded your audience.
The same thing applies to WoW, and pick your latest release game. Hell Fallout3 might run better under wine than it does in windows!
Why not adopt microsoft's implementation strategy on Win32 only applied to Linux. Right now a Linux machine running wine is only little more effective than a Windows 98 Virtual Machine... This should change Dramatically to expect people to come to linux in droves.
Don't get me wrong I run Linux in a medium sized datacenter in all the places it's right for, but until my desktops are all linux we still need Active Directory to manage the systems, and expensive Anti-Virus products running on every endpoint chewing up cycles. Give users an apples to apples experience to vista, make Wine work on 99% of software without the user having to do a damn thing. You do that, and you've got the same compatibility Windows on Windows emulation gives Vista64 and XP64.