cleaning the crawlspace...

I've been looking at and posting about the things that companies like Cleanspace do for the crawlspace under houses. I want to get soe of your opinions on what I plan to do to my crawlspace. I have a sloped lot, so my crawlspace goes fro about 6ft. in the fron to about 2.5ft at the back of the house. The plastic under the house is in bad shape and I have a lot of areas of exposed dirt. I want to put down a new layer of 6mil plastic. I thought about the whole "sealed space" idea, but after talking to some of you I have decided against it. I just want the underneath area of my house to look neat and clean as possible. So...
Here are a few pics of under my house, and I have some questions. You can see that the builder sprayed the cinder block with some type of "loose pack" insulation. I'm not real fond of this stuff. I think it attracts and holds moisture. Plus, it's just plain messy. I would like to tear that stuff off of the walls and glue up some foam board in its place. Then I though I could attach the new plastic to the foam board about 4" from the top, run the plastic down the foam board and across the floor.
Does this sound like a good plan?
Also, notice that I have open joists. I've heard that putting insulation in between them is a bad idea nowadays. Any thoughts?
Thanks in advance for your input.
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We don't ever get standing water under the house. Sure, the dirt under there may feel a tad damp at times, but it's never really even gotten what I would consider muddy. I just want to cover it up with a good layer of material as I figured exposed dirt under the house is never a good idea. Also, I wondered if that type of insulation was really good to have on the wall and if the foam board would be a better choice. Thanks.

foam board does not hold moisture, always the best for this situation.
Also, if you have not researched it yet, try Building Science Corporation for more info on what you are about to do.
good luck.

I had a similar crawl space at my first house, though it was wetter. I added a 4" perforated plastic pipe in pea gravel around the inside perimeter, which I tied into a sump. Then I smoothed the dirt out, added a heavy plastic liner which I sealed at the wall with roofing repair mastic. I insulated the crawl space outer walls and repaired the vents so that they could be closed off in the winter.

It made a world of difference - no damp smell, warm floor over in the winter and it was a nice place to store seasonal stuff.