Bike racks

My partner and I did the math, and talked over what we want to do with our bikes. We're both interested in being able to bike to camp sites in addition to commuting and utility biking. The conclusion is we need to replace our day packs, add racks to each bike, and eventually get a trailer. The trailer can wait for the right one to show up on Craigslist, and his rack can wait some. The day packs are easy since we both have hiked and hauled enough to have solid preferences. Panniers aren't as easy, but we've come to the conclusion that no one pannier will be perfect for all our intended uses. So we'll start with the urgent and adjust as needed.

Racks I need help on. I'm typically hauling 20-40 lb loads of groceries home in my backpack. I can (and do) hit higher on days where I'm doing certain sorts of pantry restocks. Are there racks I should avoid (besides the obvious just say no to seat post racks and just say no to racks rated for 25 lbs)? Are there any racks that have been especially good for the weights I'm hitting? I'll continue taking my day pack on grocery trips, so even if I hit silly weight, the load will not all be on the rack. I do want most of the load on the rack and not on my back, since carrying a heavy load on my back tends to tempt me into bad posture.

Right now I'm leaning towards the Jandd standard rack, since my local bike shop carries it and it meets my needs for weight. The price is not bad either ($50 at the shop with installation, $42 online and I'd have to install it myself).