The manual is quite misleading about mysql_fetch_array vs. mysql_fetch_row. What they actually mean is that returning database results as an array with string index is not significantly slower than returning them as an array with numeric index. However, they fail to mention the fact that mysql_fetch_array() almost always does unnessecary work. People use mysql_fetch_array(), but utilize only the numeric OR the string indexes, not both.
I also use mysql_fetch_assoc() quite frequently. I use list=fetch_row only when I feel I want to get the result back as individual variables instead of an array.
mysql_fetch_array($res, MYSQL_NUM) is equivalent to mysql_fetch_row($res)
mysql_fetch_array($res, MYSQL_ASSOC) is equivalent to mysql_fetch_assoc($res)
mysql_fetch_array($res) is equivalent to array_merge(mysql_fetch_row($res), mysql_fetch_assoc($res))
I hightly doubt fetch_row and fetch_assoc will be deprecated (at least not anytime soon). Their use is too widely spread.