You beat me to it V, I've been planning on messing with some Linux myself, keep me posted how it goes.
On RAM - IMHO its latency as much as Brand as long as its quality, Corsair Value RAM should be fine.
On CPU - This board will "un-lock" multipliers if you have a T-Bred or Barton, no mods necessary.
Yup, my $41.00 1700+ is very nice, I'm using the Volcano 11+ HSF with the adjustable fan control, last I knew it was $29.00 at NewEgg. Currently running a quiet and reasonably cool 42C @1.750V, 3500rpm. When I game I crank up the fan to 5500rpms which I can't hear through my headphones.
On HDD - I don't know of any issues with this board, however there have been some issues with disk failure with the 800JB, I lost one myself, NewEgg got me a free replacement fast though. May as well get your Seagate, they are good drives and should serve you well.
On Video - $50.00 GF4mx440 -not SE- if you look around you can find them with newer BGA type RAM, faster cores (275mhz) and TV-out. Don't worry about 8X compatability, doesn't mean much. You should really look at the MN31N it only costs $81.00 delivered at NewEgg, onboard video, excellent sound, LAN, everything you need in one board.
TV-out isn't all that its cracked up to be unless you have HDTV as the naitive resolution is much lower than that of a monitor, text is very hard to read, its good for playing DVDs and thats about it, of course DVDs look better on a monitor as well.
On cooling - The bigger the fan, the slower it needs to turn to create the same air-flow (CFMs) thus 92 and 120mm will generally be quieter than 70 and 80mm. I use Vantec 120mm fans as front intakes on all my rigs, I use 80& 92mm everywhere else. Side ducting is quite helpful, I run an 80mm in the side window of my MN31N LAN rig blowing directly into the 60mm retail HSF on the Barton 2500+ which is excellent CPU and heat sink. In general AMD has greatly improved their HSF on their retail units and they don't charge much for them, the 3 year warranty is also nice.
Both Shuttle boards have good LAN performance, the audio of the MN31N is excellent as its the MCP-T where the sound on the AN35N is just the MCP which I found lacking in game support and replaced with a SBL for $33.00
I'm not up on the Linux compatability of any of the components but I believe both MoBos are okay. You might want to come visit us over at
www.nforcershq.com forums where there is a lot more info and linux folk lurking around to help you, plus if you're interested in nForce thats what its all about. If you need a hand or have a question, I'm known as Szandor over there and every other forum for that matter
Good Luck V!
Regards, Balrog/Szandor