Can someone please explain the best macs to mod for n00bs like me? I think the B&W and the Sawtooth are good to mod but I'm curious if there is more...
Thanks

Any desktop system will do except for the iMacs, they're more for the end moder.

I would go for the sawtooth since it has a AGP bus and faster then the B&W. Both systems have a long list of mods that can be easily done.

Are there other macs that can be used?

  Anything can be modded to fit your specific needs.  Its true that some things are more tangible than others but I think whole idea is to do something that you would use. For example... If you listen to a lot of music in your kitchen, hook up a slick mp3 server... If you're bored of your tower, paint it and throw some LEDS in it... or make it look like a giant pez dispenser.  If you want to take your laptop to construction sites, wrap it in carbon fiber, and put dust filters on the vents.  Think about the coolest/useful thing you want.  If you can't buy it, build it.  If you can't build it alone, ask the peeps here if they can help or offer pointers.  If you just want to try something for fun, to see if you like modding, pick a mod guide and copy it (with adding your own flavor to it!) 
Sorry for the rant... insomnia makes me a little crabby. 

While necessity is the mother of invention which means modding something you need is a good way to go. But don't forget that many mountains have been climbed simply because they were there.

For some reason I seem to be talking in metaphors all of a sudden.

Quicksilver is my choice if you can get any Mac.  They can be made pretty quick with dp 2.0 G4s and a 7800gt.  Plus you can put them in any atx case.  Hmm, I think I just renewed some interest in a Mac mod for myself just now.  Wahooo!

Let us know whatcha go for.

well I guess the blue 'n' white I bidded for is ending in 3 hours. while I wait, what should I do with it?

upgrade the memory for sure. It can only use 256MB sticks but it can hold up to 1GB. You can overclock the CPU and add a bigger heatsink. install a batter video card like a ATI Radeon 7000 64MB PCI card and if it's the PC version you can flash it for mac. You can do the ATX power supply mod. Add two more harddrives and turn the old one into the swap partition for OSX. Add a USB 2.0 card and a RAID card. Replace the DVD or CD-RW with a super drive. Paint the case or put the internals into a ATX case. If you have money to apre you can buy a sonnet G4 upgrade CPU for it.

If anyone wants to know why I want to know about the best macs to mod, it was so I could start a guide to modding.