These cabs are extras that aren't needed to run the ROM, but are just there for your liking.
(HIT THANKS PLEASE!)
Manila Calendar Tab - An awesome member at XDA made this homebrew tab. It's NOT the HTC tab, like in the newer manilas.
Google Maps 3.2.1 - Google changed the A-GPS structure in the newer version of the Maps app, so A-GPS doesn't work as well. It works best in this version.
In-Call Recording - This is the In-call recording plug-in to the phone canvas dialer. It actually works and also enables you to record with the notes app (due to the newer wavedev.dll). The only problem with it is, it causes stylus detection to break. I can't fix this and don't plan to. If you don't care about your phone detecting when your stylus is in or out, then you can go right ahead and install this!
Sprint Navigation - SPRINT USERS ONLY- If you have the plan for it, then use this. I like Garmin and iGO8 better though, no plan needed, no service needed, so it's a one-time fee on those.
Sprint TV - SPRINT USERS ONLY - If you have the plan and stuff...
Sprint Mobile Email - MIGHT WORK FOR NON-SPRINT USERS - This application runs in the background and lets you set up one personal email account to have push-like email sent straight to your phone. The way it works: This is a Sprintified version of SEVEN and has the server send an invisible text to your phone that tells it to send/receive when you get new email. It only does text emails and it doesn't require you to have the data connection on at all times like outlook push.