This is the format I've been using til now. As I discovered during the last session, it takes up a bit too much vertical space. I'm also not completely satisfied with the structure.
This is a first cut at a completely table-based stat block. Tables in Tiddlywiki, especially tables with changing column counts, get a bit ugly to edit, so I'm not happy with this from the creation point of view. It's not saving a lot of vertical space either. Also, I suck at color schemes.
This is a mix of text and table. It suffers from some of the same layout issues as the full table above, though it avoids the annoyance of HTML breaks in text blocks to create multi-line table entries. It seems a bit cleaner overall.