You might consider getting the other gear you want ("want" being determined after reading some of the articles and gear lists posted here), then rent packs for the first two or three trips. After that, you'll have a better handle on your gear needs, as well as how you like certain styles or brands of packs (rent a different one each time), and you can proceed to pick one out to buy. REI rents gear; some local shops might, too.

As you put together your tentative gear list (for both of you), post it here and let folks critique it. It's a great way to cut through a lot of the initial wealth of information, and might help avoid some buyer's-remorse moments. (I'll refrain from the critiquing - I hike in the lower Midwest/upper Southeast, so I don't have any good knowledge about hiking in your part of the country. Others here do.)