+1

26X1-3/8 tires will not fit on the same rim as 26 x X.XX (any decimal size) tires. 26 X 1.0, 26 x 1.25, 26 x 1.5, etc. will all fit (although, as a general rule, I wouldn't recommend using a tire narrower than the rim).

For commuting, 1.5" wide tires (~38mm wide) tires are very good. 1.25" (32mm) wide tires would be ok too - 32mm is a very standard size for all-around riding. I use 700 X 32mm tires on my road bike.