Not so fast!!!!
Whether you want to use balanced or unbalanced cables depends on what you are connecting. If you're connecting your RME to a balanced input then you obviously want to use a balanced cable and have the RME switched to balanced. Your audio interface for eg will typically be a balanced device. Moogerfoogers are unbalanced, so if you're going into one of those then it's unbalanced cable and switch the RME to unbalanced.
Also, if the cost difference between balanced vs unbalanced is an issue you are definitely doing your cable shopping at the wrong place. Most people are. You can get top of the line cables in any configuration sized to your own custom length for far less than what your typical retailer charges. Redco is your salvation: http://www.redco.com/shopexd.asp?id=653
I have my entire studio cabled with premium AES spec cable at customized lengths. I haven't bought a cable from anywhere else in years. Here are the components I use in their custom cable builder:
Cable Type: GAC-2AES Gotham AES (AES spec cable - their best cable for line level connections IMO and better than Mogami gold. Mogami Gold is a star quad cable that is better for mic level signals and longer lengths.)
Neutrik connectors always..
TRS connectors: NP3X Male TRS-Silver-Low Profile
XLR: NC3MXX 3 pin Male XLR-Silver
XLR: NC3FXX 3 pin Female XLR-Silver
For unbalanced cables my top pick is the Canare GS-6 instrument cable.
Voyager RME | Virus Ti2 Polar | Juno 60 | EL8X Distressor | UBK Clariphonic | Lynx Hilo | Motu 828mk2 | Focal Twin6be