I'm not a big Linux user but as someone of you already know, Fedora distribution is on my heart. 
The last Release 4 (out today) has lots of nice features (Power PC support, OpenOffice 2.0, Integrated Clustering Technology etc.) but what is really wonderful is that this new Core 4 will include (for the first time) a virtualization software (called Xen) integrated into the system. This is a virtual machine that can securely run multiple operating systems in their own sandboxed domains.
This is really cool... Virtualization now is not only a toy for playing with different operating systems but it's a big needs for the every day life of a developer. Good to see that Fedora has open a road on this field...
I hope that Longhorn developers are listening... we've a great virtualization tool now (Virtual Server and its "little brother" Virtual PC), why not having one of this tool totally integrated with the OS core a day? 