If you are looking at my blog post lately, you will see that the next Slackware (12.1) will have much more hardware supports than previous release. This is due to the usage of newer kernel (2.6.24.x series), better udev rules (thanks to Piter Punk), and a lot of packages has been added (mostly are wireless drivers/firmware) to support more devices. This is a good sign towards a better Slackware release. In the past, Slackware seldom or rarely includes drivers like this and that's going to change (at least starting from now).
Besides the driver updates, one thing that i saw and tested for the last several days is the desktop effects from compiz that are getting better and more stable as before. When i tried to use 0.70, the titlebar wasn't disappearing again and most of the effects is working out of the box, meaning that you don't need to configure it again (except for installing VGA drivers and configure your xorg.conf). This package has been enhanced by the release of compiz 0.72 and it has been included in the -Current right now. Some new effects are available from this version, like bc and mag. Too bad, Slackware doesn't include the configuration manager for compiz, so if you want to tweak the configuration, you will have to do it manually.
There's also NTFS support due to inclusion of NTFSPROGS 2.0.0 and FUSE. It will bring excitement to people who have used ntfs-3g in the past. Now they can mount NTFS partition without having to compile external/third party package.
In the past, Slackware comes with an old red/black LILO splash screen. That will change as Pat has patched LILO and include a nice graphic as the boot splash. It's nice and cool.
Slackware 12.1 will also become more global as it will include CJK input methods also, meaning that you can give inputs using languages other than English. This is accomplished by the inclusion of SCIM-* and some fonts to support other languages.
I guess that's the most visible changes in the Slackware 12.1. I may forgotten several things, so i'm sorry for that. You can see the detailed changes in the CHANGES_AND_HINTS.TXT file, compiled by Robby Workman