Well, there are two ways they could go with this in PR speak.
If released before Windows 7:
On the positive, it implies Apple's operating system technology continues to advance at a quicker pace than Microsoft's. Apple has shipped two major operating system releases in the same time period Microsoft only managed to to ship Vista.
On the negative, Apple customers may realize they've spent $258 on operating system upgrades in the last two years.
If released after Windows 7:
On the positive, Snow Leopard will be the "newest" operating system on the market and will retain that title for years on out.
On the negative, the PC-centric press will label Snow Leopard Apple's "response" to Windows 7.
Vista's release: January 30, 2007
Leopard's release: October 26, 2007
Snow Leopard's release: August/September/November 2009
Windows 7's release: October 22, 2009
It'll be interesting to see what they pick. They might bump SL all the way to January for all we know.