If you're taking landscape shots you are really quite limited without a zoom lens. It's not always possibe to reposition and get the composition you require with a fixed focus lens when taking landscape shots. The Tokina 12-24 is a good wide angle landscape lens, it's
very solidly built and is reputed to perform as well as the L series Canon Lens. I have a friend with the Tokina 12-24 and he speaks very highly of it. Here are some user
reviews of the 12-24. The 12-24 can be bought on Ebay from
this melbourne dealer for $699. As Bert said, for portrait work, the 50mm standard Canon lens (either f1.8 or the more expensive f1.4) would be ideal as this f/l equates to around 80mm on a 35mm SLR (80mm is a f/l often used for portraits in 35mm film format). The 50mm F1.8 can be had for less than $150 and for the money is a very good lens.