If you select mod pack, on the right it should say all the mods it has in it.
The beta pack is an older version and is missing a few big mods, so I wouldn't recommend that. Direwolf20 and Mindcrack pack mostly have the same mods, but I think Direwolf has a couple more mods and the Mindcrack pack makes certain mods much harder and more time consuming. As other have said, Direwolf pack is best for starting out.
Lite pack just slims down on the amount of mods.
Magic World has just magic mods, and Universal Electricity uses completely different technical mods.