An interesting discussion and I have to say I honestly don't know what would be best.
A mixture of fun and serious items seems to have a wide appeal. I try to select the items I auction for YDC with care and always try to find something attractive and desirable - but I do try to find something that doesn't cost too much for me to buy and with inexpensive postage. I would be concerned about listing something more valuable in case it didn't raise as much as I had hoped - or indeed close to what had been paid for it.
I was disappointed (and said so at the time) that the national BCC campaign we joined didn't bring in more bidders from "outside." I had been planning to list a hand made lap quilt for those auctions but when I saw that it was only the usual extremely generous eBidders who bought the items listed in the first week (and also listed items for sale) I decided against listing it because I would have been disappointed if it hadn't raised £30 for the cause (at least) but thought it was unfair to expect the usual YDC bidders to pay that much and support the YDC auctions at either end of the BCC ones as well.
There are also, obviously, some items like the cookbook and the Xmas quilt which will only attract bids from those who know the people who contributed so will not appeal to "outside" folks.