I dunno, it sounds like you have a lot! What about it isn't enticing? Too hot? No comfy seats? We have what you listed, plus:
--shade tree w/ comfy glider underneath, good for relaxing w/ lemonade
--attached to the shade tree, a rope, a swing, and a pulley w/ a bucket
--veggie garden for me, but child sized rake, shovel and hoe for DS (from Lowes)
--wading pool, also serves as baby containment device when empty and filled w/ toys
--cozy coupe car
--toy mower, blower and edger
--tee ball stand and lots of balls of all sizes
--frisbee (dog likes it)
--hose w/ attachments like water wand and nozzle for car washing or plant watering
--flower pots w/ flowers
--a canopy over the water table and our patio set, we've strung Christmas lights over it, looks cool!
I want to get a wooden playstructure (we have a lame-o plastic toddler one) and a hammock next. When the boys are older I'd like to get a badmitton (sp?) set, maybe horseshoes. We have a bowling set made from half and half bottles but we usually play that inside.