Congratulations on your new purchase. I'm sure you'll enjoy the .58 - you won't know what you're missing in the .72 or .85, so you'll adapt to what you have. I haven't had the pleasure of trying a .58, but it'll be ideally suited to the wider angle lenses that you intend on using.
As for lenses, I don't have a 28, but if you can get your hands on a version 1 asph. 35 lux you'll be extremely pleased with the results. Can be a bit pricey though since few of these babies were made because of manufacturing issues. A lot of threads out there on various versions of luxes and crons from users far more experienced than I. I'll be watching out for responses here as much as you. Take care and have fun with the new "toy"!