Tables are just that: Tables.
They are frowned upon because they should not be used for layout, as has been the fashionable thing to do before browsers could position stuff properly.
If what you want to markup is, in fact, a table, then use a table. Other than that, try to stay away.
One small thing: Aligning two parts of text to the exact same line that won't move apart (think, username and post date). There using a table is IMHO an option.
