If you both need the articulating screen then as Rocky suggested the 650 would be a good choice. Personally, lenswise, I would go for the 15-85, it's surprising how much difference the 3mm at the wide end makes, & the 85 overlaps your 2 other lenses nicely, but that's just my opinion. I have all 3 of these lenses BTW, & the 15-85 although pricey, is a great lens, & the 2 "kit" lenses are no slouches either. Altenatively you could try getting a good deal on a 7D with the 15-85 like I did, or wait for the replacement. Canon, however are not too forthcoming with info on that, unless I have missed it. Good luck in your choice, in the meanwhile enjoy your present set-up.
There are old pilots, & there are bold pilots, but there are no old bold pilots.