I have some extra (old) Macs and PCs around the house and a MacBook that's sometimes overworked. I'm looking for tips on using multiple computers effectively.

Basically, I'd like to add to the following list. Here's what I'm using so far:

• Teleport: lets you use a single mouse and keyboard to control several Macs, like Synergy
• Built-in file sharing: lets me run programs on another Mac, but only maintain one copy of the data
• Bazaar: distributed version control
• Mail.app, Thunderbird, etc.: IMAP for my mail accounts
• TuneConnect: control iTunes on another Mac with a nice interface, using the library on my MacBook (if I choose it by pressing option at startup) over file sharing
• OmniFocus: syncs across computers pretty seamlessly
• Web browsing across computers
• VNC/Remote Desktop
• Running X-windows programs using ssh -Y hostname for headless operation (but they die when I sleep the connecting computer -- something like GNU screen would be ideal)
• Plain-old ssh with GNU screen

Really, a better idea of what I do might be necessary. Generally though, I'd like to distribute tasks across more than one computer when possible, but not have much overhead in doing so. The perfect solution? An Xgrid-like program that pushes processing across multiple computers automatically and seamlessly (although that seems unlikely).

Here's what I have, in case it makes a difference:

• MacBook (Dual 2.16 GHz, OS X 10.6.3)
• eMac (1.25 GHz, OS X 10.4.11, soon to be 10.5)
• Dell Dimension (800 MHz, some version of Ubuntu) -- no dedicated monitor
• PowerMac G3 (400 MHz, OS X 10.4.11) -- no dedicated monitor
• iMac G3 DV (400 MHz, OS X 10.4.11) -- currently in the kitchen for recipes, email, web browsing, music, movies (DVDs), etc.

(Total, they cost me around $650, mostly for the MacBook. Freecycle is wonderful, just in case you haven't heard of it.)

I'm really only using the MacBook and eMac at this point, but I'd like to push more onto it and possibly the PowerMac and Dell.