So the real question: Is buying a piece of crap worth saving $1200USD?
Since you went there, that way...
I really really tried to buy a Mac Pro.
I just could not get into the 2.26 Octo at $3200 and the Quad 2.66 felt weird at $2500 since Microcenter sells the i7 920 for $200. I know the Mac Pro uses Xeons, but really... I'll put my i7 920 up against anyone's quad Xeon. Of course I'm running my $200 cpu at 3.6GHz on air, but I digress.
I stressed a month on this, considered refurbed Octo Harpertowns and in the end, I gambled that Microsoft would get it right with Windows 7 and home built this thing:
i7 920
Asus P6T Deluxe2
12GB ram
1TB caviar black
HD4890
case, power, etc
$1200
Now before you go freak out on the "troll" just step back a second.
I'm no troll. I love my MacBook Pro and I've used Macs since they ran at 25MHz. Yes, MHz. I've had a 9500 604e 132MHz, 9500 dual 180MHz, G4 450, dual G4 800, dual G5 2GHz and that was my last desktop. I sold it while Apple wisely transitioned to Intel. If you want to talk OS 7, OS 8, OS 9, OS X, let's do it.
I'm down with Apple but they have just lost me of late as a desktop customer.
Windows 7 is Microsoft's best work in a long time, even if it is Vista done right, it's a tight OS that I have no issues using.
If you don't want an all in one iMac, and I don't... if just for the huge glossy screen alone... and if you don't want to spend $2500-$5000 for a desktop, Apple has nothing for you.
The real insult is the $40 video card. I can add ram and a hard drive to a Mac Pro, but then I have to up the video card as well?
I get it. It's an art studio computer for people who need to run Final Cut Pro. Adobe writes crap software for Apple, and they have for a long time now. Adobe has let the Copland / Carbon transition and the Flash war on the iPhone affect their product. They have no love for Apple and it shows.
Anyhow, to answer the OP... no, the 3.33GHz option is not worth it. And if you get weak one night and sip some Henny with your credit card in your lap... just think of me out there running my $200 i7 920 at 3.6GHz on air.
Apple, please, we only ask for two things in 2010.
1. 1680x1050 resolution on the freaking 15" MacBook Pro.
2. A MacPro based on the i7 that sells for under $2000.
Looks like 2010 is going to be another sad year.