Well - really it all depends on how much privacy - convenience - and 'space' you want.
You could do a family suite at one of the values - or you could rent a DVC Villa - either on rented points or renting outright from Disney.
The thing about renting DVC points that you have to remember is that you will not qualify for any Disney promotions like
free dining.
If you are going during a 'free dining' period you would need to compare costs between ALL of your options.
We took my parents for their 40th Anniversary in 2008 (we actually bought DVC on that trip) but we stayed the week at Wilderness Lodge and got upgraded to Club Level for free. It made for a GREAT and memorable week. We had two adjoining rooms and had plenty of space - plenty of privacy - and two full bathrooms and thanks to the upgrade - access to the Old Faithful Club Lounge!
With a DVC resort it's safe to assume that you will 'NOT' be upgraded. As DVC resorts rarely ever provide the opportunity for an upgrade - especially a free upgrade - especially to club level! I'm not saying you are guaranteed to receive an upgrade - but with Disney - Magic DOES happen!
For such a landmark birthday - you might want to consider checking out club level prices - it really does give a much different experience from our experience.
As far as which particular resort, well once again that depends how you consider your options.
Among the BEST Disney Resorts, I would suggest the following - and the reasons for them!
Wilderness Lodge: WOW it's just amazing - it's beautiful! If you like a really relaxing feeling when you aren't in the parks - Wilderness Lodge provides that feeling. It really feels like an escape to the mountains - after spending a day in the mountains (Everest, Space, Splash etc!)
Animal Kingdom Lodge: The ability to wake up to Giraffes eating outside your room speaks for itself! Plus to sit outside in the evenings around the fire, surrounded by animals (along with their sounds, noises, grunts, etc) really transports you to a different place and even a different time. The dark cool lobby really feels like a world away from the hustle and bustle of WDW.
Old Key West: It's a place that just tells you to kick back - relax - and watch the world go by. You will do a bit more walking - especially if you are outside of the immediate area of the Hospitality House, you could do a LOT of walking depending on how far you are away from bus stops etc. But it is a beautiful resort that I feel anyone of any age could truly enjoy!
Port Orleans: It's a Moderate resort - reasonable rates - but still many services, options, and conveniences. Plus the grounds are beautiful and among the best themes of the Moderate or Value resorts. Overall in most seasons and situations would would save $$ by staying at a Moderate.
If you would like to ask specific questions please feel free to PM me!