The Energy lumps are bullet proof engines!
Can take some serious abuse and easy to maintain. These come in 1.2 and 1.4 varients. Also, as mentioned the F7 series are nice hard pulling engines with a nice engine note, but aren't as easy to work on as Energy lumps (being larger capacity and 16 valve)
All of them suffer from rusty arches and sills as well as leaking sunroofs, dodgy electrics and general bits falling off.
If it's your first car go for a 1.4 RT. Not too bad speed wise for a 1.4 and the interior is comfy, plus thy have a few electrical goodies. Stay away from the 1.8RT as these are five door only and although the engine is strong, it only produces 95BHp and isn't as revvy as the 1.4.
I had a 1.4 RT for about 14 months and it was a great little car. Stood up to some abuse but never let me down once. Bought the car for £230 as a write off, drove it for 8 months with the head gasket blown and she still ran and ran!
For £1000 you could get a minter of a 91-96 year model.