http://store.steampowered.com/app/287450/
Rise of Nations was a fantastic RTS in a similar vein to Age of Empires. While many of the gameplay elements are similar to that of AoE, but it had enough new mechanics such as attrition, a bit of a research tree, unique resources on the map you needed to control, that it brought something new to the RTS genre at the time, and it still holds up solidly today. And now it's getting a similar HD remake to what AoE2 had! Full steamworks integration, updated visuals, the usual.
£12 pre-order price, or £36 for the 4 pack (£9 each).
If there's interest, I'd be interested in splitting a 4-pack!