Sleep should work fine with Windows 7. I set all my installs to sleep at 30 and Hibernate at an hour.
In the rarest cases, there are problems which are normally resolved by updating the Display driver
If not, I next check the Diagnostics-Performance log for what's happening at sleep or wake time once it's logged: troubleshooting steps
Next try the clean boot by turning off all Startup items in msconfig or CCLeaner>Tools except AV and gadgets. Next in msconfig>Services choose "Hide all MS Services" to see what's running without your knowledge, uncheck it, then check back in both locations for programs which turn themselves back on to turn them off in their Preferences or Uninstall them. You now have a clean boot.
Finally use the tool which the Pro's use to trace these issues which will present a multi-dimensional chart of your Resume to see what's hanging. If needed the top expert on this and author of the trace Cluberti will consult on your trace results: Gathering a Startup, Shutdown, Sleep, Hibernate, or Reboot Trace