My girlfriend has an E60 520d, and I really like it. It's definitely brisk enough when it needs to be, and it's a lovely comfortable place to spend time. I also think they're really good-looking cars - they've grown into their looks over the years
Considering it's going to be your everyday car, I'd consider dropping the M-sport spec, essentially because of the wheels. The smaller wheels/larger profile tyres will likely be quieter and more comfortable, less likely to get damaged during everyday use, and cheaper to replace the tyres on. (Note that the run-flats for them, on larger rims, are heinously expensive. My GF's cost ~£1000 for all four recently - thankfully it's a company car!)