Install new kitchen cabinets and counters.
Re-floor the entire house.
Raise the front porch and install new porch columns.
Convert the un-used back room into a master bedroom and laundry room.
Install built in bookshelves and cabinets throughout the house for greater storage.
Fence the backyard, possibly with privacy fencing.
Create a nice back yard for relaxing using xeriscaping techniques.
Increase the energy efficiency of the house.
Repair/Replace the old windows.
Install a new front door.
Replace all of the hollow core doors with solid wood doors.