I found a brand of tires that are a breeze to install and remove:
Tioga PowerBlock in the 20 x 1.60 size. They're fast on the street, very resistant to punctures (so far), give a comfortable ride (65 psi) and
can be had for $18. If you want higher pressure, you can get the 20 x 1.40 size, although I can't vouch for their ease of installation.
A word of warning, though....being that these are BMX tires, you will feel compelled to seek-out dirt trails and unpaved roads (I've been spending time riding the property around a condemned cement factory in the industrial side of town). It's good fun. The look I get from mountain bikers is priceless.