any particular current pattern preferable?

So, the new 75 is sitting in the front room, filled these four days now and set up with the stuff the store suggested, except the filter, a Marineland C-360, which I prefered because it's for a larger volume of water. It's connected - four trays of stuff, half of which are totally unfamiliar to me - perking merrily, and two Aquaclear 50 powerheads, one on either side. There are filters to go with, but they're not attached at the moment. My question is, where should I point the powerheads? I have them close to the bottom and pointed in the same direction thinking that that would create a circular pattern but would feel more comfortable with a more knowlegeable opinion. I'm awaiting a collection of nice starter plants from MA and wonder if they like such strongly moving water, or if in fact, it wouldn't blast them right out of the gravel. This tank is 48X18X20. Any enlightenment will be welcome.
Thanks, Jackie

The powerheads are for water movement, only. The filters that go with them attach to the intakes but are not connected at the moment. So, I'll turn the powerheads sideways and point the outputs towards the surface. That sounds more plausable so far as plant growth is concerned, too. Good to hear the filter choice was a good one, too. Thanks for your advice!