I'll say Utley, Berkman, Braun, Hamilton, Dunn, and Gonzalez.
Had Utley not been sidelined with injury, he would've come close to 40 HR last year and will at least come close this season.
I think Berkman can do it on a good surge yet, but the odd thing is his groundball rate hasn't changed much.
Braun obviously hasn't had the sample size, but June was a blistering one for him and even if that 8 HR week had proven, he can hit them in bunches and has the potential to come around with a couple of 10 HR months.
Hamilton should keep pushing his HR total up to 35 or more, given that he's benefited greatly in hitting in Texas, and should continue as he rolls into the summer months.
Dunn can usually be counted in for 40 HR anyway.
Adrian Gonzalez has been a surprise in that the splits haven't been that lopsided as expected between his home/road power production. I've always thought he could generate 40 HR power if he didn't hit half of the year at Petco, but he doesn't seem deterred by Petco's spacious dimensions and sea breezes thus far. It will be interesting to see if he can still churn out some power at home.