A state-of-the-art kitchen is one of the most popular renovations for earning back most, if not all, of its investment. Even if you don't fully gut and renovate, certain upgrades --granite counters, hardwood or high-end tile floors, premium appliances (especially stainless steel), islands and undermount sinks -- attract attention and can increase value.
2 Hardwood floors
Especially on the main floor, hardwood is perennially popular with buyers. If your floors are refinished but worn, have them lightly sanded and resealed. If they're very beaten up consider replacing them.
3 Premium broadloom
Broadloom is popular too (especially for bedrooms), but only if in top condition. If it's worn, soiled or out of fashion, replace it with something more contemporary. Neutral, lightly textured weaves such as wool “sisal” are fashionable right now.
4 Master ensuite
If your ensuite is a bit tired, it's worth upgrading, especially if you can afford a few luxuries such as a whirlpool or air jet tub, separate shower with a rainshower head, double sinks and/or heated floors. If you don't have an ensuite, perhaps you can install one by stealing space from the master bedroom or a room next to it.
5 Radiator covers
It's a simple carpentry job, but makes almost any older home seem more gracious.