Thank you for all of the responses, everyone! I'm looking at the Thermaltake Frio. Do you think it would fit without having to remove a heatsink from the motherboard? I suppose I could always buy it and just exchange it if installing it is too much trouble.
If you use a 120mm x 38mm fan then you can only use slots 2,4 & 6 with tall heatspreaders.
Did you mean slots 1, 3, and 5? Slot 2 looks to be the closest slot to the motherboard. In any case, my sticks are currently in 1, 3, and 5. Does it make a difference if I move them to 2, 4, 6?
Night Fox, thanks for the link to the graph and chart. There's some good information there!
Finally, patonb, I thought about cutting some holes in the case when I was first putting everything together but decided to put it off. As you can see, my cable management is pretty poor so I think I may work on that when I get the chance. From what I can see in the picture and based on my memory of the inside of the case it looks like you only made the one hole near the PSU. Am I correct? I would very much like to see a picture of the inside of your computer if you have one available.