Best practical accessories?

[ukwildcat]

I'm finally getting annoyed with the minimalist accessories that came with this beast, and I'm going to buy some new ones.

I have a few questions / concerns, however.

Floor mats
I've had all-weather floor mats in my previous vehicles and I consider this indispensable. Are the BMW-branded mats of suitable quality or should I look elsewhere? (WeatherTec, etc.). Should I match them to the interior color or contrast them? (matter of preference I suppose but one way or the other could look out of place too)

Cargo
I need some cargo nets. Probably the "luggage" one and the one that stands upright in the back.

Should I get a carpeted floor mat or another all-weather option? I don't haul a lot of "dirty" stuff in it, but I do from time to time. I would think the carpeted mat could be easily cleaned, and there isn't a "mismatch" when the rear seats come down for cargo.

Does the grocery thing work worth a flip to hold those cheap little plastic grocery bags?

CARGO COVER
I know this one is touchy.. Mine did not come with one and they won't cough one up. But I have to have it, and this brings me to..

Where's the best place to get these? I know there are other places, but a little looking shows that pricing is similar and of course at the local dealer I can simply pick them up.

Any advice / recommendations "get this" "don't get that" etc. would be appreciated.