I’m pretty conservative as far as monsters go. I prefer using the classic Humanoids as the general antagonists (orcs, bugbears, goblins, gnolls, etc), along with trolls, ogres, giants, classic undead (skeletons, zombies, wights, spectres, ghouls, Liches) and demons. I’ll throw in some of the more mythological creatures from time to time (perytons, chimera, cyclops’, & griffons for example), as well as some of the classic D&D monsters that appeared in the 1E MM or OD&D like rot grubs, mind flayers, ropers, beholders, etc…
But I just don’t get in to many of the D&D monsters that started to come out as the game really grew in popularity. In fact, I find most D&D monsters absolutely silly..things like the Githyanki, Yuan-Ti, Phaerimm; Cloakers, plane-touched, tieflings, genesai, celestials, etc...and then 3E has gone even farther off the silliness scale AFAIC: Half this/half that, templated this/ templated that, ethereal filchers, Warforged, pseudo-mechs in Chainmail and Eberron, etc., etc..
This is why I don’t buy 3E/D20 monster books. I have 2 monster books besides the MM, and thats just 'cos at the time I bought them I supported both companies products as much as I could..I didn't really need them, and only liked a handful of creatures in each.
However, I really, really like the Lejendary Adventures “Beasts of Lejend” book…lots of cool mythological and classic fantasy-like monsters, and some interesting spins on the D&D clichés. That book is definitely “my style” and I would pay good money for it in a d20 version.