As discussed in the Macworld article Set newer portable Macs’ sleep mode, it is possible to disable the copying of RAM onto disk when you put a MacBook or MacBook Pro to sleep. I’ve found the recovery from sleep to be more reliable with this feature disabled. Going to sleep also takes much less time.
I’ve included the relevant portions of the article below for the curious. For the impatient, running the following commands in Terminal will change sleep mode to RAM-only, and remove the memory image file:
sudo pmset -a hibernatemode 0 sudo rm /var/vm/sleepimage