Good link Bored of the Rings.
I personally have three versions of Blender:
for general modelling needs i've been perfectly happy with the latest version 2.78, i haven't found any issues with it so far.
I have 2.69 on my machine because some people recommend using 2.69 instead of the latest, apparently there are some issues with flipped normals when exporting to .X on the later versions, but I've never in the year and a half I've been using it encountered that issue, so I've never actually had to use 2.69, it's still there just in case though.
Because that version has a working .X importer, which i've found great for importing .X models then saving them as a blender file and editing them in 2.78, you just need to remember to rotate them on the X axis by 90 degrees, and apply the rotation because 2.49 used a different axis system.
i5, NV960 2GB, 16GB memory, 2x 2TB Hybrid, Win10.