Olavk makes good points, and Corey gives a great detailed explanation. Reading Corey's info, though, gives me a conclusion of Olavk's answer. Keep in mind that depending on what you're doing with the information, you may end up 2-staging your query. Find the item, then for each reference, do a direct select on what was of interest.
Also consider the idea of storing everything in multiple tables and reading it from a single table. I do this for a large database I have where most of the queries need certain common information, but the full multiple table layout is still required. The inserts are slowed down a little by the triggers that they kick off (in my case, one per file where each file is responsible for up to a million rows inserted), but my later select queries can go from minutes to single digit seconds.
Data warehousing :)
