Hmmmmm....mantis tank with some softies.
I'd go with 150 watt MH with a 20K bulb. Most softies doent have high lightening needs and a 20K would make everyting pop. I also personally love the shimmer and blue water.
Next question is: Canopy or no canopy. If you going canopy, skip the MH and go with T5's or PC's.
There is no real wrong choice, just a matter of aethetics. Look at pics of what other people are doing and see what you like.