Well the wait is almost over and then we all can start looking forward to IE9 RC and maybe the first leak of windows 8! LMFAO
Wave 0 = RTM Wave 1 = RTW There are over 625 hotfixes included in SP1, spanning causes of bsods, handle leaks, memory leaks, deadlocks, performance issues, multimonitor issues, interprocess issues, application compatibility and windows 7 graphics platform updates. The fixes pushed through WU can be considered a handful of the total amount of fixes available for windows 7.
RTM = Release to Manufacturing, or the process of making CDs, putting them in a box, and then getting them out to customers. RTW = Release to Web, which is making something available for download.