As everyone has said RME is truly one of the best and none of it is going to be inexpensive. But you are build something that can likely last several years as a motherboard / CPU combination. If you can afford the RME, you can't ever second guess yourself about having taken that route.
My MOTU was relatively high end in 2004 and it , as an audio interface , has performed perfectly with Cubase for 9 years. It was only an issue initially in 2005 when MOTU had inexperienced coders developing their firewire drivers. It is a nice feeling clicking this thing on and off for 9 years and having it never screw up. Just like my F-150 with 289,000 miles. It's just does the job
Cubase Pro 8.0.5 | Win 7 ultimate | MOTU 896HD | I7 4770K 32gb Corsair Dominator Ram |ASUS Maximus mobo