Here are some things I like:

SONAR Performance Optimizations
How can you not like this?  I haven’t had a huge problem with projects in the past, but do notice a significant decrease in resource usage in this new version, all the same.

Dedicated Instrument Track
This is more of an organizational preference than anything else- but I do find it a bit cleaner than the old way of grouping a midi and synth track within a track folder.  Another good thing is that you can switch back and forth whenever you want and apply the feature to only those instruments you want.  Very flexible!

Dimension Pro
Very similar to Dimension LE that shipped along with Sonar 7 PE- the most noticible thing for me so far is that we get over 7 gigs of material with the pro version.  Wow.

Z3TA+ / Integrated Step Sequencer
Two tools from the previous version I feel compelled to mention here since they are just so great.  Z3TA+ is a waveshaping synthesizer with a wide array of options for generating some really, really incredible sounds.  The step sequencer provides an alternate midi pattern generation environment from the traditional piano roll.

TL-64 Tube Leveler / TS 64 Transient Shaper
Any tools that give me more control over the sound are always welcome.

TL-64 provides intuitive controls to determine the level and character of analog tube saturation, from subtle “warming” to hard-driving saturation. The TL-64 plug-in features a unique selectable Dynamic Response Filter control that when engaged employs a dynamic (versus static) tube model algorithm.

Here are things I could care less about:

Beatscape loop performance instrument / Loop Explorer 2.0
I don’t work with loops… so this is pretty useless as advertised.  However, as with many other tools, it may be useful when applied in some other way?

Native Instruments Guitar Rig 3 LE
Similar to above… I wonder what running some vox through this would do…

I’ve been using this software since version 3 and normally upgrade every other version.  I obviously have broken that tradition with the purchase of Sonar 8- the overall improvements on an already solid piece of software were too good to pass up for another year.  There are lots and lots of other things to mention, but these are some initial observations after a week of use.

More nformation can be found at http://cakewalk.com/Products/SONAR/.