A lot of people will suggest that you make a goldcard (and its really easy) just in case something goes wrong. I know there's a TELUS RUU floating around somewhere so you can get it back to stock if something goes wrong.
But for me, I flashed a RUU update for Froyo (2.2) a few months before I rooted because I couldn't wait for TELUS. So I already made a goldcard prior to rooting. I suggest you do the same, it really wouldn't hurt and its a pretty easy task to do.
I kept hearing Leedroid was good but I haven't really checked any other ROM. But when I checked the thread for Leedroid's ROM in XDA forum, I noticed quite a few Canadians are using them so I went with it as well. If you want as close to stock as possible then teppic's ROM would be a good choice but the A2SD+ is an addon if you want it (not sure how you go about flashing it because the A2SD+ option is included in one of the version of Leedroid's ROM). I'm sure someone can help you here to flash teppic's ROM if you want that. So it really depends on what you like, I went with Leedroid's because of A2SD+ since its the main reason why I rooted.
Don't forget to backup the files you have on your SD card and also do a Nandroid backup and Titanium backup before you venture onto flashing.