According to www.tv.com ,these are the top episodes so far
http://www.tv.com/veronica-mars/show/24272/top.html?tag=subtabs;top

To me it's
Pilot
Leave It To Beaver
I Am God
Spit & Eggs
An Echolls Family Christmas
A Trip To The Dentist
Like A Virgin
Cheatty Cheatty Bang Bang
Hi,Infidelity
Rashard & Wallace Go To White Castle
Blast From The Past
Versatile Toppings
Welcome Wagon(Except for the ending)
Ain't No Magic Mountain High Enough
Witchita Linebacker