After wrestling with wheel bearings over the years and now most recently with some very, very corroded rears out of my '08, I found the best tool to date on removing these damn things.
This set of pry bars, I use the 12" for wheel bearing removal. Narrow enough to get a bite but long/strong enough to smack it with a 5lb sledge.
http://www.harborfreight.com/hand-to...set-68339.html
Get the inner wheel spacer tilted so you can get the pry bar tip on the inner lip of the old bearing, then WACK. Done. No more chisel, stake or screwdriver attempts.