If you want something upbeat AND fun, make sure to get a few CDs by ApologetiX. They do parodies that are right up there with Weird Al. In fact, they are called the Christian Weird Al. I would highly reco the albums Biblical Graffitti, Ticked, and Grace Period to start with. They have 7 CDs, but I don't listen to one at all, one barely, and the three I listed all the time. They even parody Bruce Springstein's Nicki song. Man, It cracks me up thinking about how funny their remake of Simon & Garfunkle's Cecilia into Cornelius. Great stuff!
I would also reco: the Gaither Vocal Band's Everything Good CD, the Hawaiian Homecoming with the Gaither Friends,
For vocals: The Martins album titled Glorify, Edify, Testify. These three brothers and sister can SING like mad. Anything by Pearl Brick would be really enjoyable as she has an awesome voice, and I own both On the Other Side and Songs from the Chapel. If you want some Celtic influence Maire Brennan's album Perfect Time smacks of Enya's vocals. For a 20's swing theme I would go with The W's album the Fourth from the Last. For rock with some Chicago horn flare the OC Supertones album Hi-Fi Revival is KILLER. A capella I would reco The 7th Element.
My favorites of all time for rock are the Newsboys. I have 5 of their albums and would reco them in this order: Thrive, Take Me To Your Leader, Going Public, Love Liberty Disco, and the Step Up to the Microphone. These guys are VERY talented and often funny, but have some real depth to their message. dc Talk's Supernatural is another MUST HAVE in any collection as it is simply stunning it is so well done. Track 3 is my favorite. Nice test for soundstaging and imaging.
That would be a good beginning. If you want any other suggestions just PM of post another thread.