I have used one of these - almost sexual experience - if I ever win the Lottery - I will have one.  

http://www.game-revolution.com/games/hardware/intensor.htm

Puny imitations. ^

The one I used was a full size chair and had WOOFers in it. It also had force feedback pedals and twin josticks. Believe it ir not it was on the sales floor at a chain that CompUSA bought out.

When a bomb went off it rattled your bones.

You can come close with a good speaker system and a four channel sound card. I have a Logitech 5 speaker system and a AW840 sound card. I put the front speakers on the desk and mounted the rear ones on my chair with some mounts I found at Radio Shack. For the sub base I used some L brackets and bolted it to the back of my desk chair (you need the tall back chair). The trick is to get the sub base close to your body. With this set up I can feel the gear lock when I put them down or up.

When I first had it all set up I tried it out with Delta Force LW. I made a scenario with five blackhawk helos flying around my position. I soon got bored watching them fly around and started shooting at em with a M60. It sounded like the cat was playing with something beside my desk but I noticed the cat was asleep on the sofa. What I was hearing was the sound of the spent cartridges hitting the pavement at my feet. It sounded that realistic and explosions would almost take your breath away.

In FS 2002 I got the improved Baron sounds and when doing a full power climb the walls of the room rattle. Expense wise I didn't pay much more for it than I'd have had to pay for a more simple system: Sound card was cheap $20.00, Speaker system $79.00 (Got mine on sale for $59.00, Brackets $3.00 and it's a good thing I live way out in the countryside.