The importance of the nav and idrive are more than just looks and..er nav. It provides a level of integration that gives you more convenience over cars without.
If you want iPod integration and control - you can get this with the nav/idrive cars (you need the usb socket in the glovebox too). This will also give you better bluetooth intergration with your phone (this can give additional features like bluetooth audio streaming, internet and BMW apps depending on addition options).
I was never really sold on the whole idrive and nav option, but once you have it, you realise you wouldn't want to be without it.
Cruise comes as standard with the SE spec, or at least it did on later cars. There's plently choice out there, so don't feel you have to miss out on the spec you want.