That floor is rather clean for a hellacious den of evil with a massive sacrificial pit. I recommend dirtying it up. Something like this:

Click image for larger version.  Name: sacellum-lolth-dirty-floor.jpg  Views: 55  Size: 1,009.5 KB  ID: 68479

That was done in Photoshop, using the following procedure:

1) Opened the original map in Photoshop
2) Snagged a nice grunge map from cgtextures.com
3) Opened the grungemap
4) Used Image > Adjustments > Desaturate to make the grunge map black-and-white.
5) Pasted the grunge map on top of the original map as a new layer
6) Change the layer mode of the new layer to "multiply" and set its opacity to 67%
7) Added a layer mask and masked off the pillars, walls, and altar.

That adds a bit of variation across broader areas so that the floor tiles aren't always perfectly identical. In the original file you probably wouldn't even need to mask anything -- just put the grunge layer underneath the pillars etc.