Given all the lively discussion on the right solution at defensive tackle (and by popular demand), I've pasted some links to a series of articles I recently wrote addressing the topic. Ellis-obsessed Broncos fans beware: the results may surprise you. Here are the links:
Triaging Denver's Defensive Line
Redressing Denver's Defensive Line: Draft-Day DT's
Your questions, comments, and criticism are most welcome. Enjoy!