Thought I would help slowly recover from the spam attacks and get some help in the process.

What is preferable specs (generally speaking and considering it will be a used machine) for a server running a minecraft server? What's important, and what's not? Won't be a 24/7 server (maybe 6 hours a day) and will host me and 5 friends during the week but as many as it can take at other times (if I have it for fraga it will be 24/7 creative for as many people as possible.

Our group has been taking turns running a bukkit server during the week on our personal rig but we are going to need a dedicated rig soon that any of us can just remote into, but I have NO idea what I should look for in a box, and sure you guys are more knowledgable then me when dealing with servers

If you have one for sale let me know via PM with pics and price

Note: it must have at least a VGA connection so that I can hook it up once in a while to do maintenance where remote would be a PITA.

Thanks in advance guys!

Depends on how many people you're expecting to use it at one time... You can host a small handful of people on pretty much anything. Any more than that and you'll want lots of RAM (at least 768 Meg), and a little bash/batch script that warns everbody, saves, then restarts the server every 6 hours or so.

Minecraft has a memory leak, so it continually eats RAM and will eventually freeze up your box unless you reset it once in awhile. You say you're not going to be hosting for more than that at once, so you may be OK.