Are the Bots and spiders counted under users?
My forum has seen an increase from 20 members online to 200 users including spiders.
And on an average my forum uses 35-40 GB of Bandwidth per month.
Which cheap and reliable host is recommended for me?

I have a dedicated server with hostgator. i normally have at least 100 users on my forum at a time and i've been very happy with hostgator. speed has not been a problem since switching to them and for the most part, their customer service/support team is outstanding. as with any "level 1" type environment, you'll run into the occasional person who is just phoning it in....but I would definitely recommend them overall.

i have never had to wait on the phone (or their live online chat system) for more than 5 minutes....and it's usually less than 2 if that helps.

speed ok... but. they have so many restriction.... we cant put adbrite inline on it or your board will be suspended as spam .... i suggested NO.. big NO...

Host Gator is the worst hosting company I've ever encountered.

I highly don't recommend them!