Well, this is a loaded question. You'll get a bunch of RIGHT answers.
Let me first comment about lasers: Point them where there is NO CHANCE IN HELL that they'll get into people's eyes. Either onto a back wall or ceiling or some other place where they can't get into eyes. AND NOT off mirrors that could reflect back down into eyes. Other than this, the rest of this post is more opinion and trial and error stuff.
Some effects work "better" in certain positions. For example, I think the Revo series looks best aimed OVER the crowd(like, above heads) and with heavy fog. But you can certainly aim it at the floor with light or haze. In stand-alone(no fog or haze), this light isn't that great. With the heavy fog, you can get some freakin' awesome effects out of it.
Lights like the Vertigo, Mystic and Sunray III(lights I own) work best being aimed OUT away from the fixture and hitting the walls, ceiling and floor all around. The Vertigo has the smallest coverage pattern. The Sunray III just slowly rotates, sort of a "mirror-ball" substitute. The Mystic covers a large area. These all work better with fog or haze though. The Mystic works great when aimed at the floor or wall with or without fog. The Sunray III and Vertigo just pop better with some haze or fog.
Scanner-type fixtures: I have the Electra, Rover, barrel Flex and Reflex. These I aim INTO the floor area. Mine are older low-draw fixtures(50 watt bulbs). These work good, but without fog, they really seem silly. Haze is OK too. People like these dancing in and out around them. The Barrel Flex and Rover also pop light onto the ceiling too because of the Barrel wheel. In my case, these are ALL non-intels.
I also have a Trilogy and Double Twist. Works fine with or without fog. Nothing special but have been good and cheap.
Onto fixtures I don't have that you're mentioneing: I don't know what the MBT's are, so I wont comment. Chances are, aim off the stage and above heads and you'll be fine. Dont know what the tri-phase is and my internet sucks so I can't risk looking it up.
Quad Gem: So many options. Out into the audience, above audience, from stage back truss to front stage floor. Use fog or haze to make the beams pop. You'll love it.
Strobe: best placement is really variable. If you want brightest for crowed, point into dance floor. have a mirrored ceiling? Aim up. Want to mainly light up your area? Point into stage. Strobes will bleed light everywhere but always grab attention. The main thing is how much attention to you want. People overall like strobes, but don't use it a whole lot just to be safe. If you are using it, use it briefly. Not saying you can't use it a lot, but this is one that you don't want to over-use. The first concern is they could trigger an epileptic condition, and the second is you don't want to annoy the crap out of people by constantly running strobes. I personally don't like strobes that much, but am glad my 64 LED Pros can do strobing because it's a handy thing to have. I'm also planning on getting an actual DMX strobe. Just use good judgment. It's best to under-use it than over-use it. I feel all DJ's should have a strobe, it's a handy effect. And most lighting companies should have a strobe in inventory even if they don't bring it to all shows.
You can definately point stuff at the ceiling. I like doing this with my movers, often using a rotating gobo and/or a color wheel. If you can cover a larger area, this works best. But if you have a moving yoke fixture, you can aim this everywhere. You don't want to point everything into the ceiling, people don't want that. They want some lights hitting them from time to time.
Cans: I use these mainly for bands to light them up. When I do the Sac Club Rave twice a year, we aim these out into the crowd. We dont really focus too much, just 8 random locations works good for that event.
Same event: Lights on the truss shoot through the stage and into the crowd although a lot gets lost into the stage area. These fixtures would be the Mystic, Sunray III and Vertigo. Since the head DJ/MC likes to bring people on stage, we lose a lot of good locations to mount the truss and lights. But I have ideas for next year involving LTS-2 stands and T-bars to get stuff off the stage and into the audience. I still will continue to place that truss backstage though.
You've got a decent selection of lights to get started, plus room to grow. How do you plan to control these?
Your biggest issue is: How long does it take to set it all up? That's the thing I'd be most concerned about. You can get away with fewer lights if you rotate through them, or at least break it up. Having extra lights, you can choose to leave some at home. That and how much pre-set can you do(like, leaving cans on T-bars and in cases to set up/strike faster).