I've got friends with mediocre systems, and decent rooms. But speaker placement in a given room is just as important as both issues mentioned. Separation is one topic which comes to mind. And if they need stands, by all means LIFT 'EM!
Example #1. Friend has a nice old H/K receiver and some garage sale Klipsch Hereseys ($50 score for him!). He has the speakers sitting on the floor, both in the corner of the room, side-by-side. This puts the horns at shin level. Not worthy. And you can imagine the lack of imaging, being side-by-side.
Example #2 (woman this time): She has a decent mid-fi HT rig. And she insists that the (tower) main speakers "look better" flanking either side of the stereo cabinet. Maybe so. But the center channel speaker is on top of the TV, to the right of the left and right speakers that are sandwiching the stereo cabinet. GGGgggrrrrrrhhhhhh!!!
Obviously you see the problems with both of these scenarios, and both have simple remedies. PLACEMENT WITHIN A GIVEN ROOM is the best place to start. Then consider changing rooms or speakers. Just my $0.02