75 is not a lot more $ than a 55g, from there, at least in glass tanks the 90 and 120 have thicker glass and a big price jumpHermit said:Welcome!!
One word of caution. A 55g is a nasty size. I have both a 40 and a 55, and much prefer the 40 because it is deeper. The thiness of the 55 makes it hard to aquascape. Just my 2-cents.