I know plenty of DMs like to roll their dice in the open. I, however, usually don't. Not to hide rolls so much as to hide notes. I use the Dungeons & Dragons 3.5 Deluxe Dungeon Master's Screen. Honestly, I don't reference what is printed on it much. Most of that info is already burned into my brain. However, I do usually have adventure notes printed out and paper clipped to it.
Battlemats are great. Be they the do-it-yourself kind or the beautifully-done pre-illustrated ones, they make gaming with miniatures a breeze. However, I usually use Heroscape tiles for my terrain. I love the customization you can do with them. Yes, they are a hex grid instead of squares, but I honestly find that to be easier. No diagonals to worry about and circular spell areas fit better. I'll admit, the Heroscape tiles work best for large outdoor enviornments, but they can work for indoors to. When this was still fairly new I picked up the first master set for around $40, and an online search turns it up anywhere form $32 to $50 now, so it's a pretty good investment for some cheap 3d terrain. Not to mention the master sets come with several miniatures that you can use as long as you aren't overly concerned with scale (they're slightly larger than D&D minis). So here's some examples of what you can do with Heroscape terrain:
This is one of the scenario maps with the original master set.
This is one of the maps buildable with the newest master set. Yes, those are Drow, this is a D&D themed set. By the way what you see there is every terrain piece in that set. If memory serves correctly, the only mini missing is the black dragon. Not a bad deal for $20.
Lord of the Rings, anyone?
Ok, a note on the next few pictures. These are made with who-knows-how-many different sets combined, and you'd have to spend stupid amounts of money to recreate them, but they are pretty awe-inspiring.
Well, I've got to run, so part 2 coming soon.
All of these images were taken from various sources via a Google image search. To find out where they came from right-click and select properties. Those people own and have whatever applicable rights to the images.