The sad news is that a ReadyBoost drive will do nothing to help your out-of-memory situations like running games, Visual Studio or Virtual Machines - it doesn't get added into the available RAM pool. ReadyBoost really functions as more of a disk cache.
That being said, a ReadyBoost drive might help alleviate some of the I/O bottlenecks and improve performance slightly in some of the more intensive applications - like Visual Studio - if your tasks often involve fetching data from the hard drive (like during a compile/build).
I would suggest using the Resource Monitor or Performance Monitor and keep tabs on how much pressure is on your CPU, RAM and Disk I/O. You might find that you are really CPU limited, or maybe if your disk read queue length is constantly above 1.0 you will get lucky see some benefit from the ReadyBoost drive.
Also, you are probably hitting your pagefile pretty regularly, you might want to check and make sure it is properly defragmented with a tool like PageDefrag from the Windows Sysinternals group at Microsoft.