I'm on record as being a reverse size queen (or king, as Lex put it). I am a non-versatile anal top, so, much as I understand a preference for big dicks in those looking to get fucked, their criteria is largely irrelevant to me. I do love sucking cock, however, and again, like Lex, prefer to not be unduly challenged, especially by girth.
I understand that I am very much a minority in this regard, but I find small dicks (especially on a muscular man) extremely masculine and intensely arousing. My ideal man (in theory) can be described this way:
1) Muscular with an added 15-20 pounds of flesh, especially in the backside;
2) Smaller than average penis with extra overhang on his foreskin: there is never too much foreskin for me;
3) A tough, street-wise, feral attitude: I likes me the bad boys;
4) A sexually adventurous risk-taking insatiable powerbottom with as few limits as possible;
5) Between the ages of 30 and 50, and HIV+, of course.
I usually end up with Latinos (evil Latinos are my Kryptonite), so my move to South Florida from New England in 2003 increased my pool of available beaux tremendously. I'm totally open to Europeans, Africans and Asians who otherwise meet the criteria (many do), but your average-white-guy American with a larger cut dick and goody-goody, romantic notions about fidelity and cocooning with "the one" holds absolutely no allure for me whatsoever.