Strider 2 for the PSone, simply because I wanted the NTSC-J version. I could have got a PAL release for a fiver, but I wanted the import version. After missing an Ebay auction for a copy that finished at about £12 (due to stonedness) I was determined to get the Jpn version. Took a while but I got one for £20 inc. shipping. Bonus.
Also Mickey Mania and Earthworm Jim for the Mega CD. I refused to pay more than a fiver for PAL MCD games. So I didn't, just took a little waiting.