1. Schmeichel
2. VDS
3. De Gea
4. Seaman
5. ???
Yeah, pure bias. De Gea have the potential to raise to the top, his game can improve even more. VDS was impressive since before he joined us, his performance at Fulham is classy, just wow. I really don't get this lazy claim "VDS is only a top level keeper because of Rio-Vidic". Even before Vidic and Evra raised their game, VDS was already keeping our famous leaky defense back then tight and organized (season 05/06).
The fifth one is tough to say. As impressive as Cech and Courtois are, they had the advantage having 2-3 layers of walls protecting them at Chelsea. Tbh I think Cech is more impressive pre-injury (I both admired and feared him) than Courtois who is all-around just a darn solid keeper, nothing special. Cech is special before that. Given is also impressive at Newcastle, exposed defensively.
5. Cech/Courtois/Given.