What game should I get?

[TinCow]

You could try Caesar III. No diplomacy and limited military, but it's a great city-builder.

Thanks for the suggestions, HOMM 3 sounds interesting but is there any reason why you pick 3 and not 4 or 5?

HOMM4 was very poorly done. HOMM3 is a far better game all around. HOMM5 won't run on your laptop (I think).

I highly recommend getting the HOMM3 'Complete' version, which has all the expansion packs in it. One of the pack introduces 'combo artifacts' which are very, very fun in the single-player campaigns.