As shown on 43rumors http://www.43rumors.com/special-bhphoto-rebates-on-sigma-and-lensbaby-stuff/ (would like to direct link but not sure the sales would work that way, whatever.) Anyhow, none of the sigma things are interesting me right now, but I've been thinking a long time about finally getting some monitor calibration, and two seem like pretty good deals on this--the X-Rite Colormonkey Display ($144), and the Datacolor Spyder4Pro($125). I know this could to in the "This or That" forum as well, but some questions about these: a) are those actually good deals, and b) which one do people like better? I'm having a hard time comparing because I've never used anything similar. I'm a rank amateur c) something else instead?