What do you look for in a forklift?

I'll keep it short. I've dreamed of having a forklift for quite some time, but it was always just a "want." As time passed, the "want" has grown into a "need." So, having never owned or even operated a forklift, I've decided to once again reach out to the brain trust here.

I'll use the forklift mostly for handling steel plate and tubing, but also for loading/unloading machines like lathes and mills. I think a 3,000-4,000lb. forklift would be very sufficient, and it would be a bonus to have the capability to drive through gravel and dirt.

Some things I want to learn: pros and cons over gas/propane/electric, is side shift a necessity, older models vs new?

My budget is about $3,000 and there's a decent number on the used market in that range, I just thought I'd ask around for input.

Also, what considerations should be taken when transporting the forklift?