We have a irregular shaped pool and we are building a rectangular pool in our vacation home now. I love our odd shaped pool but I have found that trying to buy a solar cover or any type of cover for it is difficult and much more expensive. To make the rectangle look special (sounds boring to just have a rectangle) :-) we are putting in a tanning legde with side to side steps going down to the rest of the pool and a sheer descent waterfall. We are also using copper colored glass mosaic tiles.

Personally, I like the geometric shape of the rectangle better. I think it is like anything - trends will come and go - free-form/lagoon-like is in right now, rectangle/geometric were popular before, and they will probably come back in like bell bottom jeans and shag rugs. We have an odd T-shaped, 35K gallon pool and any kind of cover (solar, safety, leaf) are all just outrageous. I wish we had a simple rectangle, it would save a lot of trouble.

I also vote that rectangular is more contemporary looking, so perhaps the style of your house may be influential in the shape you choose.

I have a kidney shape, it nestles up against a curved stone retaining wall. I do like the shape, the curve, etc. Only thing I wanted was a nice 40' straight run with a bit of perpendicular wall at each curved end for swimming laps and flip turns.

It's an informal pool in a sort of informal setting. Muted pool colors, etc. Lots of trees around.

If you have kids, a rectangular is better for pool sports. Volleyball, etc.

Try looking at a Double Roman End pool it should not cost you that much to upgrade to this shape because of the panels not being as curved. I build more of these than any other shape and some brick coping or flagstone to dress it up...