I'll put in a vote for the DeWalt 735 planer, I certainly have not regretted my purchase (though I bought mine a few years back when the Lowes price was $499 and I had a $50 rebate). I also added the Wixey digital gauge to my 735, which I also recommend for precision, though the 735 has a decent depth gauge as-is (just not as accurate as going digital). I seldom suffer more than 0.001" of snipe with my 735 and often times zero snipe -- and I do not even have the optional support tables. My only gripe with the 735 lies with DeWalt's pacement of the exhaust port, which they centered over the outfeed table -- which requires the user to tie the dust collection hose off to the side so it stays out of the way of exiting wood.
If the 735 is too far out of your price range (though a 30% off certficate is handy on an item that mostly retails at $600 lately), then I would think that you would not regret the purchase of either the DeWalt 734 or the Ridgid thickness planer, both seem reasonably well built and have had their share of positive reviews. Any of these 3 choices purchased as used equipment in excellent condition would be outstanding buys; you just don't get any warranties on used gear.
With respect to blade availability on the DeWalt planers, Home Depot seems to be hit or miss as to whether they carry these blades (and many no longer carry the 735 in their stores, though they once did). Lowes seems to carry blades for all 3 DeWalt planers (at least in my area) at round $50-55/set. Even mailorder is not that big an inconvenience, a set of blades should last you awhile, so it's not like your likely to be swapping them every few weeks (I keep 2 spare sets on hand so that I'm not affected by occassional lapses in local availability).