Yuri_Rage said:
I am curious, however as to whether the end state system will be noticeably faster/leaner than Ubuntu.
That's kind of an unfair trial, unless you're really benchmarking equal configurations too. You described your system as having "plenty" so I doubt you'll find the optimizations much use at all. If you want to see a fast system, build up something minimal. Debian and Arch linux are considered some of the fastest.
You can speed Ubuntu up noticably by removing services you don't use. The Ubuntu vs Gentoo comparison will side heavily towards Ubuntu if you factor in download and compile times in "total cost of ownership".
One of the best things I've heard about Gentoo's supposed "optimization" at the compile level is that "-03 doesn't do much except expose compiler bugs".
Yuri_Rage said:
xen is not free - it has a free trial.
Xen is free (gratis) and free (libre) since it's actually a heavily modified Linux kernel itself. Most distros include Xen, some by default.
Ubuntu -- Details of package xen-hypervisor-3.2 in hardy
You suggest you virtualize
Virtualization rocks, though I prefer KVM. It's a part of the default Linux kernel since 2.6.20 and Red Hat just purchased the company that maintains it (Qumranet) so it will be supported even more, while the company that purchased Xen is Citrix, a Microsoft Partner. I'm not anti-microsoft but it should be obvious which company will be more aligned towards useful and complete virtualization for Desktop Linux users.
Can they run Microsoft Enterprise applications like Exchange '07 and SQL '08?
No, Microsoft bundles those products to their Windows operating system. There's nothing directly compatible/comparable to Exchange, but there are things as good (I'd argue better) than MSSQL.
Are they native 64-bit OS's?
The super duper technical answer is "No, Linux is not an operating system". It's a collection of tools that can be mixed and used as you see fit. This is because the source code is publicly available and the license allows you to use it where and how you see fit. Because you have that source code, it runs just fine on 64-bit platforms. but it runs on a LOT of platforms (ARM, i386, AMD64, SPARC, MIPS, Power, et cetera) and depending on which specific application it may NOT have been developed FOR that architecture but almost always works fine on it.
Good enough for you?
If not, grab a LiveCD and give it a spin. You can run it live, without installing though you should know that it will be slower (CD read speeds suck compared to HD reads) and that some features might not work fully (due to being partly or entirely read-only).
Also, Microsoft Virtual PC allows you to virtualize on Windows so that you can run a different operating system WHILE running Windows at the same time and when I last used it, it was still free to Windows users.
Microsoft Virtual PC 2007 download