This list is customisable with some simple url additions.
Adding ";board=x" where x is the board number will only show recent posts on that board. So for example, https://bitcointalk.org/index.php?action=recent;board=159 will only show recent posts on the ANN board.
You can string multiple boards together by changing "board" to "boards" and separating their numbers with a comma. Example: https://bitcointalk.org/index.php?action=recent;boards=67,159,224 will show several altcoin boards.
You can also use the modifier "c=x" to watch a category. Mouse over the headings on the main page to see the category numbers. Example: https://bitcointalk.org/index.php?action=recent;c=1 will show all the Bitcoin boards. Categories are as follows:
Bitcoin - 1
Economy - 3
Other - 4
Altcoins - 6
Again, you can string categories together with a comma.