I been using SPB Mobile Shell 2.0 since I got my Omnia and now is upgraded to version 3.5 by SPB Software.
So what so nice about version 3.5? Installation is easy but you need to have at least 12MB of RAM to install the program.
After installation you have 2 types of screen:
a. Professional
b. Lifestyle
The cool thing about version 3.5 is the widgets, so no need to use 3rd party widgets. The widgets are:
Other nice features are
a. Email (like like cards, you flip thru the emails)
b. SMS (like like cards, you flip thru the sms)
Here a little about Windows Mobile 6.5, according to Microsoft, Omnia 2 can be upgraded. So hopefully, Samsung opens it to Omnia series too :)