I suggest going with 108" fabric, that way there is no seam. A yard of 108" equals about 2 1/2 yds of 44". Sometimes it is cheaper to go with the 108" because its less expensive than the amount of 44" fabric you would need.
Say you're doing a king size that is 100 by 115. That would be 2 3/4 yds of fabric at say $15 yd, costing aprox $43. With 44" you would need three 44" pieces of 2 3/4 yds to cover it. or at $10 yd costing around $82.
We have quilters who buy the 108" and cut some off the use on the front, thereby tying the front and back together.
Backing is not just muslin any more either, it comes in many colors and shades.
Lanny