The only time I recommend against firstlast.com is when you've got a last name that's either more than 8 characters or might be hard to remember how to spell/remember.

I registered my lastname.org/net (.com has been taken for years) but I know for a fact that since people are unable to pronounce it (I've had maybe.. 5 people throughout my entire life thus far be able to pronounce it and that's because 3 of those 5 were Polish as well1).. I went ahead and opted to stick with "FirstMiddle" instead. So I registered riane.org recently as I felt jordanriane.com was feeling a bit too long (even before an email username is added!)