I have old hardwood floors in my home that I'd like to refinish myself. I'm ok with all sorts of manual labor, but I'd like to know the preferred method for refinishing them without damaging my walls or baseboards.
The random-orbit sanders don't have nearly the risk of grooving that the belt sanders do, and these ones also have a built-in vaccuum which collects a large portion of the dust, unlike the sanders of my childhood.
I've sanded both floors of my house using that system; each floor took about a 3-day weekend start to finish using a process similar to this one. I did find that I needed to use a hand-held belt sander for the edges, and since our floors are not all that even we used it to get the existing finish out of some of the deeper spots in the floor as well. If you pull out your trim and use some care you should be able to get right to the edges without having to do more than touch up the paint on the trim.
We just used the water-based polyurethane and have been quite happy with the results, but it's absolutely worth it to put down as many coats as you can - we ended up doing 4.
I rented the Varathane sander as mentioned in the other post from Lowes. I also purchased the water based finish and sanding disks. There was an instruction booklet with the sander that walked you through the process. I used a handheld random orbital sander to sand in the corners. The entire process cost about $150 and took two days. I sanded down to the bare wood the first day, cleaned up and put one coat of finish on. I put 4 more coats on the next day with a light sanding before the last coat.
For amateur use I would suggest considering one of the floor sanders that uses four 6" random-orbital discs rather than one large one. Rental is a bit more expensive, but they're almost idiot-proof. (Very much so compared to the old belt-sander versions, though I've seen beginners succeed with those too.)