I can't help you with the texture vs. no texture question, but I can tell you that adding a quilted all-cotton mattress pad over a memory foam topper takes away the heat/no air circulation problem...at least it did for me.

I have had trouble with regular memory foam toppers making me hot, even with additional cotton mattress pads over it. I finally found a cool memory foam topper that I love.

http://www.overstock.com/Bedding-Bath/Comfort-Dreams-Mem-Cool-3-inch-Memory-Foam-Mattress-Topper/2622925/product.html

My memory foam topper came with a layer similar to the one I've linked below. I still put a quilted cotton mattress cover over the whole thing to protect it. I love the idea that for around $200, you can improve your sleep as much as if you had spent $1,000+ for a new mattress.

Here is a link that might be useful: Great Idea

Thank you both for the help. You can see that I was a bit sleep-obsessed, it being 2:00 AM and all.

I'm thinking I need to have both bumps and a cover.

One of the reviewers on O said that she wouldn't buy any less than 3 lb density nor any less than 3 inches. That made sense to me. I wish I knew what density I was sleeping on at the moment.

I like the cool one you linked to, Judie, and I'm leaning toward that exact model right now. Some of the ones that say they are ventilated actually have little perforations, I think, which you would think would make them less dense. Why does everything have to be so hard to figure out? I just want somebody to sell me a perfect night's sleep, night after night. Right, yeah.

I bought ours several years ago and we love it! I then went on to buy one for our guest room bed and one for our daughter's bed. When DS was in grad school, we bought him one for that bed. Two years ago, I sent one to my parents for their Florida home and they tell me that they've never slept better than they do on this topper. They went out and bought one for their Michigan place, as they said they couldn't sleep without one anymore (LOL!). All have the different comfort body zones. The only suggestion I can give you is to buy the 2" or 3" toppers and not the thicker ones. When I was looking for mine, several people on a decorating forum like this told that they'd purchased the thicker ones and none of their fitted sheets would fit over them. All of the ones we now have are 2 1/2" or 3" and the fitted sheets work fine with them.
Lynn

We love memory foam toppers. Costco used to have amazing (white) ones, but when we got a king-sized bed, we had to buy a new one, and it is blue and very disappointing. It buckles and slides around. We're very upset.

So, if Costco has white ones, it might be worth a shot.

Here is a link that might be useful: Bad New Costco Topper