A set of sheep clippers, or big set of beef heads are probally the worst thing to get for a beginer, trying to get by with just one set of clippers. I would tell you to get a set of Laubes. They are more expenisve, but have 10,000 spm(strokes per minute) compared to the Andis 4500 spm. The laubes, Andis(the past 3 models that thye have came out with), Oster A5's and a few others all use the same blades, and have many different blades to choose from. The Laube's, andis 2 speeds, or a set of Oster A5's.
For blades I would suggest getting the following
#10 Wide- clipping heads, and tail heads (works simaler to a set of large beef heads)
Medium or Blending blade- for blendings necks, and all around clipping
Also a 5/8's is help full for ruffin out the neck, Some people use a T-84 but I havent, After you have clipped with the blending blade for a while you can get a X-block, opti-Block, or another blocking blade but beware because they are VERY sharp they cut to the tips meaning it will almost shave it bald, or if you accidently stab your hand when clipping it make for a very nice hand Falay(I have had it happen!)
Also another clipper that will work is the new Wahl Switch blade, I havent used them either but I have seen some of the big boys at shows using them(but then again they were givin them)