Santa brings 1 fun toy each, some books, and small stuff for in the stocking (socks, candy, etc.)
Gifts from my husband and me are usually stuff they need, 2 or 3 things per kid. This year they are getting Taekwondo sparring gear, new baseball bats, and clothes (the TKD gear and baseball bats are things they will be required to get for their activities in the next few months anyway, so we are buying them now as gifts).
Plus each of them buys a gift for the other.
All together, my kids will open between 5 and 10 gifts on Christmas morning, some small and some bigger, some are things they need and a few are toys.
In response to your SWH: He is only 6. It's his job to test limits and it's your job to enforce them. Definitely don't take away Christmas, but do limit it to what you can afford. It doesn't have to be a huge pile of gifts to be fun.
Also think now about your response on Christmas day if he asks for the other things on his list. When mine were 8 and 5, they came to me on December 26th and said "Since Santa didn't bring us XXX (a really expensive present they asked for), can you buy it for us today?" When I got over my shock, I told them no, I didn't have $ to buy it, but if they wanted to save up their money, they could work towards buying it. They saved all their Christmas $ from grandparents and I made a chore chart and gave each chore a pay rate. I got a pack of $1 bills from the bank and when they did something on the chart, I paid them. It took them 6 months (a long time for kids that small), but they did eventually earn enough to buy the item. I think we all learned a lot and I now know that 6 years old is not too young to start teaching kids that money has to be earned, and how much work it takes to earn enough to buy expensive things. My little one who was 5 at the time (and now age 7) is now really good at looking at prices and deciding if things are worth their price tag or (as he sometimes says) a rip off.