dmi, is there a reason why these types of patterns are more advisable to buy that others? Are the patterns you mention applies also to .net domains?
pronounceable 5L .com's have a potential market future for web2.0 startups and so forth from a brandability standpoint.
Honestly speaking,the 5L domain is good and it highly depend on your domain keyword. If you found one and then register it instantly before grab by other people.
Wow.... I had no idea! I feel so proud to own one now! Seriously, I think it needs to be pronouncable and brandable. Something like TUQAQ.com is CVCVC and it's not going to be worth much of anything... but something like MUNNY.com doesn't folow the pattern and it could be priceless. It's all in how you market the domain and what people are willing to pay.