CrossRoads, I already thought that SPI to USB could possibly be a good way to go because of the low load SPI has on the Arduino. Thanks for the advice!
Is there some hardware that I could simply connect to the Arduino and then use the SPI library to talk to the computer?
robtillaart, unfortunately there is not a lot of room for compression here. The data sent mainly consists of an ID byte to identify the sensor the data is coming from and the data itself (byte or int). But thanks for the idea!