Been a long time since I've had to buy various computer accessories to run Linux machines, but here's a quick list:
- Monitors. We've tried both the ASUS PB27Q and the BenQ BL3200PT. They are both pretty amazing monitors. I really liked the extra size of the 32" monitor and at 2550x1440 it is really nice. But price wise from Staples and Amazon you can get the ASUS for $470. While the BenQ is amazing but at $650 (Beach Camera or PC Mall), it is probably not that much better
- Mini Keyboard. There are many crappy ones out there. We got a very small one from Adafruit that was basically usable. But, the GMYLE is basically a USB duplicate of the Mac Keyboard (without the number pad). Perfect at $15 from Amazon.
- Mini Monitor. If you've got a small computer like a Raspberry Pi, it is nice to have a small monitor to see what is going on the console. The mainline use is as a field monitor for video and movie production. We bought one from Adafruit for $160 which was 7 inches and 1280x800 and has speakers (the model is $10 more at $170). It is decent and fits well. It looks like the Lilliput 669GL but is 1280x800. Adafruit also has instructions about how to set the config.txt properly, so pretty useful
- Tool kit. What every geek needs is a set of hex keys and tiny screwdrivers. Amazon has a page all about this. Lifehacker has a good overview and likes the iFixit (a great site) complete tool kit at $60. The big advantage of the 54 bit iFixit (which is $24 on their site and $30 at Amazon) is that it includes all the strange screws (pentalobes) that are now in use. But if you want the ordinary Torx, then the . But there is a complete bit set from Olympus for $18 and a chinese no-name for $9 are just fine.