Of the scopes you've mentioned, I have personal experience w/ the Nikon Prostaff and Leupold. I've been very happy w/ both of these. I don't have any of the new Redfield's, but a friend has bought a couple. He's been very pleased w/ them, as well. I've read good reviews Hawke (I considered one for a varmint gun) as well as Vortex scopes, as well.
Going the used route is also a good idea, as mentioned by an earlier poster. Keep an eye on internet gun/hunting forums. I've also saved some $$$ through the years buying factory refurbished scopes from Natchez