I would recommend personally against any iPhone theme.
The first thing you need to realize about your Mogul is that it is better than an iPhone. You wouldn't go buy a Corvette and make it look like a Geo would you? (Haha, no offense to anyone who drives geos, just making a point).
On a more serious note, those looks take a lot of memory and you have a limited amount to work with. I at times shy away from any today screen skin or plugin because of this fact. In reality, it is the only big drawback this phone has from being, in my mind, "perfect".
Definitely check out no2chem's roms though. His version 5060 is tons more stable and fast compared to the stock ROMs. If you are feeling extra special 5065 is his newest and I have been running it with no problems. Read the "Flashing for dummies" threads in the Titan Upgrading forums and those will help you a ton.
In the PocketPC Software, check out sMMS program. It is the complete and total solution for lack of the ability to send picture mail from the Mogul. Is a beta software but seems to be extremely stable and works great.
On a side note, both no2chem and SomeGuyMMS deserve any donations if you enjoy their work.
That should keep you busy for a while
