While it is nice to get something that doesn't remind me that I need to clean...I would love to have a nice vacuum cleaner given to me...lol But it would have to be high class...like a Dyson or something.
I usually always ask for stuff that I can use in the kitchen. I got a new mixer last year, some new pans year before that. But I LOVE to cook and bake.
Gift cards can be nice (And are easy to find even last minute)...Give her a gift card and offer to watch the kids while she takes an afternoon to go shopping and maybe hang out with friends.
Also, I was given my first gift card for a massage last year. LOVED IT!!!!