Quad meshing is preferred where ever possible, but in this case it appears as if you have fillet radii at the edges of the main body which would cause problems. Partition off the main top and bottom sections (flanges) by extending the faces, and then you should have top and bottom as structured regions (green) and the web as a swept region (yellow). It probably won't mesh though due to the fillets. I'd consider cutting the web away completely to leave it as a seperate region that could be meshed and then tieing the faces back to the flanges. If not, you'd have to extend the edges to partition the flanges and work from there.
corus