At least for the near future (3 to 6 months) if you on the Intel platform, you should have no problem finding ATX motherboards. Look for Intel to start the move toward BTX at the end of Q1 2004. The bigger question is, will motherboard makers still offer ATX motherboards for the latest Intel platforms or will Intel force them to offer new motherboards only in a BTX form factor? At least at the moment, we don't know the answer to this question.
As for AMD owners, AMD has made no indication that they will be moving toward a BTX form factor. So, AMD owners at least for the time being will continue to be on the ATX platform.
Some case manufacturers have indicated to me that while they might be offering some BTX model cases for some of their most sucessful models, don't expect them to move to BTX quickly unless it gains a lot of traction quickly, which I beleive is unlikely since at first the BTX cases as well as the motherboards will be more expensive than their ATX counter parts.
As for which case I like better. Personally, I am a big fan of the Wave Master, while it uses an 80mm configuration for cooling, depending on the fans selected it can be some what louder than a 120mm single front/rear configuration. If I were to pick between the two, I would most likely opt for the Wave Master, but I must admit as I said in the article, that the front fan intake on the Wave Master is a bit more obstructed than the P160. Depending on your application, either case can be an excellent choice.
Personally however, I like the Coolermaster ATC-201-B-BXT much more than the Wave Master, due to the no front door configuration and the 2 3.5" drive bays, along with the excellent open front grill which in the stacked 80mm fan configration is able to push a lot of air toward the rear of the case.
As I have said before, I think that it is difficult to say that one case is better than the rest. Depending on the user and the applictions, you will have to be the ultimate judge on which suites you best. For example, I tend to personally shy away from case with doors because I used my optical drives too much burning discs and changing CDs for example.
I love the Wave Master, it is a great design and I highly reccomend the case, but it might not be the best selection for every application, but the black high gloss paint finish on the one that we had in the lab was exceptional and made for a great looking case.
The P160 on the other hand does a lot of things very well. The 120mm front and rear fans will appeal to many who want a lower noise solution with excellent air flow. The P160 has a lot of features that are very atrractive, but I for one am not a big fan of the mirror finish on the front bezel which would land this case in my "not my first choice" pile for my personal use.
Unless you are a die hard Intel fan and committed to the next generation motherboard and processor from Intel, then I see no reason why your selection of an ATX case would be a bad choice, unless you are sure you are moving to BTX in the future.
One additional thought, several case makers that have cases that feature removable motherboard trays have indicated that it might be possible to offer a replacement tray that would support the BTX form factor. We are not sure how viable an option this is yet, but it is a possible option that we might hear more about down the road.