X Server 1.7.5 doesn't have much to offer beyond the 1.7.5 release candidates from weeks ago, but mostly smaller changes scattered throughout the X Server code-base. Pater Hutterer in announcing the X Server 1.7.5 release had mentioned, "This one is the last scheduled update. The patch flow is slow enough now to
stop the fortnightly tarballs and do releases on a need-per-need basis." In other words, an X Server 1.7.6 release could come about, but only if the need really arises with an unforeseen situation.
The X Server 1.7.5 release announcement can be read on the X.Org mailing list. X Server 1.8 should be released in just over a month, but some distributions releasing in the coming months (such as Ubuntu 10.04 LTS) are sticking with the X Server 1.7 until H2'2010.