studded gloves/shirt/legs & plate helm/arms/gorget
add a broadsword if gains slow down
i find i have to adjust between studded and plate armor about once every point to find the best combo for gains. i.e. trade out the plate gorget for a studded one, etc. that will take you all the way to 120, it just takes time.
rico, i have stealth > 100 on a few chars because they don't have any armor slots left for +stealth items. i have stealth/hiding on more than half my chars.
generally to get to GM level stealth:
[50-70] reg clothes
[70-85] studded shirt, studded legs & studded gloves
[85-90] add studded arms & plate gorget
[90-93] add plate helm [switch back to studded gorget if gains are too slow]
[93-100+] add broadsword [add plate arms if gains are too slow]