The industry standard seems to be the 1X9, simply because it is a versatile twist. Others, like Glen Zedeker (sp?) advocate the demise of the 1X9.
Sure, 55grn fodder will "work" in a 1X7. I believe that the government went from 1X12 in the M16A1 to 1X7 in the M16A2 to accomodate a shift from 55grn ammo to 62grn ammo. The story goes that 1X7 is a bit "fast" for the issue tracer rounds which caused premature barrel wear, so the 1X9 came into the forefront.
If you're using your AR as an all around rifle, then your barrel twists will suffice. If you want to start shooting serious competition, then you might want to think about a free-floated Krieger 1X7.75 or a 1X8.
But don't sink any money on new gear until you learn to read the wind, work the pits, shoot from position, etc.
I think what you have is fine. When you need to replace your barrel due to throat erosion, then get something new that meets your specific needs. Don't let anyone talk you into something just for the sake of getting something new.
Unless you want us to, and then we'll tell your wife that it was our fault!