Glad you liked the bike
If you type portable recorder into ebay, you end up with a pretty wide cross section. On the other hand, if you want to drool over things you can't afford, try the Marantz PMD660, the Edirol R-1, or the Core Sound PDAudio. Korg do some nice gadgets too.
I would point out that with most cheap digital recorders you don't get control over the level. If you take my bike track as an example, the AGC would have pulled the level right up at the start, then dragged it down when the bike went past, creating a very unnatural sound. I use an ancient ex-professional Sony TC-153 cassette deck btw, very good, but very heavy.