What, specifically, are you looking for?
The biggest reasons I like CZ's are:
1. Ergonomics. This will vary from person to person, but their grips feel like they were molded to my hand.
2. Steel Frame. This is sadly becoming more and more of a rarity, but I really like steel framed pistols. The SP-01 is the softest shooting 9mm gun I've ever fired.
3. Hammer-fired DA/SA. This is also becoming rarer, but it's my preferred action type. A lot of people also like them because they can be carried cocked and locked.
The CZ-75B is the flagship model - it's an all-steel, DA/SA semi-auto chambered in either 9mm or .40 cal. Due to Cold War politics, CZ never filed for patent protection on the 75; as a result, there are tons of CZ-75 clones available from EAA, Canik, IWI, etc. They're excellent guns and are generally extremely inexpensive, but support and accessories are a little harder to come by.
The 'B' is used to designate that it's equipped with a firing pin block. The original CZ-75 did not have a FPB, and those early models are highly sought after because of the rarity and because many feel that it has a superior trigger as a result (I'm personally skeptical of this claim, but it could be true).
The standard model is equipped with a thumb safety; they are also available in decocker versions, marked with a 'D' at the end of it (CZ-75 BD). The CZ-75 Compact is steel-framed with a safety; the CZ-75 D Compact/D PCR are the alloy-framed decocker versions. The CZ-85B Combat is an ambidextrous version of the 75.
The SP-01 (Full-sized, steel-framed, thumb safety), SP-01 Tactical (Full-sized, steel-frame, decocker), P-01 (Compact, alloy frame, 9mm), and P-06 (compact, alloy frame, .40 cal) are mechanically the same as the original 75 line, but have an accessory rail and slightly different grips. Magazines are interchangeable with the 75 line.
More recently, they released the Omega line of pistols, which have a simpler trigger mechanism and can be switched between decocker and safety. The Omega trigger is better out of the box than the original, but as I understand it, it doesn't smooth out as nicely over time.
The CZ-75B Omega has the same steel frame as the original, but with the Omega trigger. The P-09 (full-sized) and P-07 (compact) are polymer DA/SA pistols. I have yet to shoot them (though I've fondled a few), so I can't give you any first-hand reports on them. P-07 and P-09 mags will not fit in the 75, but the full-length 75 mags will fit in the compact P-07 (they are too short for the P-09).