Hi B.,
I'm thinking that you meant you DON'T hate her...not that you do. :)
Here are some ideas that I hope might work for you...
1.Perhaps you can check out FLYLADY.NET, then tell her about how you found this great website on helping you to declutter your home and that you could use her help to not bring things into the house that you either don't love, won't use, or have no room for and that someone else could and would love, use, and have room for. That goes for things besides what she's given you, too. :) Freecycle is great for that!
2. Suggest that for future birthdays, give you non-space-taking items such as movie tickets, cash, etc.
3. Tell her while you appreciate the thought behind the gifts, they really aren't "you", "you and your husband", "your family", or "your decor" for "YOUR HOME". 4. Maybe suggest a shopping trip so that she can learn your tastes in design, frugalness, etc. Perhaps her thought behind those gifts were to "pamper" you as you sound fairly frugal in your buying habits (a VERY good thing, especially these days). Perhaps also suggesting a gift card to Cub, Rainbow, or Target to help with monthly expenses...promise her you'll get a little keepsake thing for yourself and she may be okay with that. With the economy as it is, and you working weekends to help make ends meet, she should have no trouble understanding this and shouldn't take it personally.
5. If she wants to lavish her only grandchild, ask her to start a savings account fo him for college and keep the toys, etc, to a minimum and small enough to fit in his room.
6. Perhaps your husband can have a talk with her as it also sounds like she is still buying things to decorate his room...comforter, game table, desk, etc???
Sorry this is scattered and long, but I just jotted thoughts as they came. Good luck!