Hi Bryan
The classic focal length for a portrait lens is ~80mm which is the equivalent to ~50mm on a crop frame sensor such as the 400D - a point in the range that your 18-55 covers.
I'm not sure if your 18-55 is one of the earlier ones or the mk II IS lens. The performance of the latter is significantly improved over the non IS lens. Either way the Canon 50mm f1.8 is something of a bargin at ~£90 and delivered fantastic performance once stopped down to f4 or so
http://www.slrgear.com/reviews/showp...uct/150/cat/10
For a wide angle the Sigma 10-20mm f4-5.6 EX DC gets great reviews from everyone who uses it.
Interfit do a twin head studio flash kit EX150 Mark II for ~£240 - I've not used it but I suspect that one might quickly outgrow it. I'm looking at the Bowens Gemini 200/200 2 Head Studio Kit at the moment £509 at Warehouseexpress - £440 in Jessops
its in a different league build quality wise