Deviantart is great, but you have to look for some of the better art there... there is alot of good work that gets lost in the masses of mediocre works. The trick is to followa few good blogs. Generally when you find one, you find its linked to more good stuff...
Here's some in my bookmarks:
Design is Kinky » Blog Archive » Gui Borchert - from the guys who organise semi-permanent, an aussie design conference
ΠŸΡ€ΠΎΡΠ½ΠΈΡΡŒ, - found this one today with the help of the above site
Lost At E Minor: Music, illustration, art, photography and more - this one
mcbess - this guy has an interesting style
The Official M.C. Escher Website - Escher is one of my all-time favourites...
home - Shaun Tan is one of my favourite aussie book illustrators, he did
The Lost Thing, The Red Tree, The Rabbits and
The Arrival
Great to hear you can draw! But I'm not sure what I can suggest for about the imagination part. I guess, like drawing from life, drawing from the imagination takes practice...