I've driven many different luxury cars and can recommend a few things...i like benz', but if you're not gonna spend at least 70 k can. (50k u.s.) to start, don't bother. C class mercedez are not worth the price at all. Go out and get a different luxury brand for a cheaper price...You mentioned you like the suv, well to be honest with you I would say the mercedez SUV is one of the worst luxury products on the market. The car looks like a box and doesn't have the total package feel of the X5, and comparing it to the FX 35/45..soon to be 65 - hahahah, goodnight.
If you really have the bones to throw around and consider purchasing a benz, go out and get an AMG. The performance on those models is sickening. Complete car, they vary considerably in price - the cheapest model C32 AMG starts around 52, good car, mind you i'll take it's rival the M3 over that anyday
Personally, as much as i like German-made vechicles, i would take a long hard look at any infiniti car before i made my decision. That company is dominating, simply put, they are taking all the awards...
p.s. not sure if you're adverse to BMW or not, but the new 6 series are F%^*&#( stellar!