iPhone: Probably nothing major on firmware. That's more of a WWDC thing. iPhone Nano, definitely this year but maybe not at MacWorld which has traditionally been a computer oriented product launch/refresh expo.
iWork/iLife Updates, hopefully iPhone & web compatible versions. They'd have an opportunity to land on a lot of Windows desktops with a good mobile version of iWork. The iPhone integration might come in the form of an iMovie app that can do basic video recording, editing and publishing. Perhaps some GarageBand instrument & remote controller stuff.
Desktops: I think this is where the biggest announcements will be made. It's the one area in Apple's product line that is seriously lacking.
New Mini: NVIDIA chipset. Probably not much cheaper but a better value at least. Maybe a little wider and taller.
Mac: Cheaper i7 based mid-range tower. Cheaper, not necessarily cheap. Probably still $1k+ or even $1500+
iMac: NVIDIA chipset.
New mice/keyboards: Anytime Apple refreshes desktops them seem to do new keyboards/mice to match. Probably a black key version of the aluminum keyboards and a new mouse -- maybe also aluminum. Perhaps with multi-touch. (basically a rounded/molded thermal sensor integrated into the front of the mouse)
Snow Leopard: Probably won't ship till April or May but there will probably be some new features announced. They may be focusing on core OS improvements but I'm sure there are some user oriented features we haven't seen yet.
Apple TV: Big changes but maybe nothing at WWDC.
1) Platform change to NVIDIA's ARM CPU.
2) It will run off the same code base as the iPhone OS with one common code base but some big GUI changes:
- The current Apple TV GUI becomes the iPod app
- The system boots up to an iPhone style home screen
- Core apps like Safari, Mail, iTunes Store, Google Maps, etc get moved over with some UI changes also.
4) SDK / ATV AppStore. This is the catalyst behind of all the above changes. The model that works for the iPhone would apply perfectly to a set top box. You'd have games of course, streaming media apps of all kinds. There's also a pretty good market for straight up utility apps -- home automation for example.
Moving the ATV to ARM means Apple doesn't have to do much work to make this happen. They already have the whole infrastructure / SDK in place for the iPhone. I don't think the apps would truly be portable between platforms due to UI differences and differences in processing power but it would be pretty close. The Wii has proven bleeding edge HD graphics aren't the end-all of gaming. Simple iPhone 1:1 ports wouldn't be bad at all -- with the option of developers targeting the ATV natively for more power.
Death Watch: I personally don't think Jobs is sick but he will resign as Apple CEO in 09. What we're seeing now is just Apple laying the groundwork. The rumor of Jobs being sick is perfect cover for it. They gotta take Jobs out of the public eye for a while to ease the transition. If investors see someone other than Jobs go out and launch a successful product they will be much less antsy when Jobs leaves. They'll understand it's not the end of the world as we know it. Jobs would probably still be involved in the more long-term goals of Apple, in the same way Gates is still involved with Microsoft, but someone else will be running the day-to-day stuff of a CEO.