We have gotten into a pattern with our relatives where they ask what the kids want and are genuinely looking for ideas. They know that we have too many toys and that we like to receive "experiences" instead. Favorite gifts are sporting equipment, music lessons, passes to the movies, and for the older kids, gift cards or $ for clothes and shoes.
My 8 year old is funny, he just likes having money. People will give me $ for him to pick out a gift and he just has me put it in the bank and then goes around telling people how much he has ("I have $463 in my bank account!") or bragging that he *could* pay for something extravagant but then he never wants to actually spend it.
My 14-year-old son knows appx how much his grandparents/great-grandparents/aunts/uncles put towards gifts for him so he maintains a never-ending shopping list in his head. About a month before birthday or holiday time rolls around, I get the "hey if anyone asks what to get for my birthday, there's a cool pair of sneakers that are normally $ but on this website they're only $ and shipping is $ if you use this discount code so if Mimi and auntie C give me $ you can use that money to buy them." I don't know if that's greedy or just practical. As soon as he gets a card with $ in it, we're shopping on-line or at a store within a week. He's not one for delayed gratification.
My 14-year-old SD just shrugs when asked, so DH usually comes up with suggestions for her that involve clothes, music, art supplies or boxing/kickboxing equipment and clothes.
My youngest son is happy to have anything that wasn't already owned by someone else, so we usually end up requesting toys or clothes for him.
I try to give anything but toys for gifts for family and close friends. I try to get creative and usually try to get something useful but fun (snorkel, goggles and flippers for the pool; sleds; movie tickets; art supplies; sporting equipment; personalized backpacks or beach towels, etc.). I don't think it's offensive to suggest things that aren't toys, but if you have someone on your buying list who LOVES to give toys (my mom loves to give dolls, for example) then let them go ahead and give toys if they want to.