Sangakkara and Lara's ICC ratings graph compared:
(Graph can be enlarged by clicking on it)
One thing that I think points in Lara's favour is that he faced the likes of McGrath, Wasim Akram, Waqar Younis, Brett Lee, Donald, Warne, Murali, Vaas and Gough 5+ times in his career, whereas Sanga faced the likes of Anderson, Ajmal, Harbhajan Singh, Kumble, Pollock, Steyn, Johnson, Morkel, Broad and Tahir.
Lara also squared off 31 times against a dominant Australian side (during a period when they amassed 100 wins and 32 losses with a 27.62 bowling average), whereas Sangakkara played 11 matches against an Australian team that were a slight notch below (62 wins, 20 losses, 30.08 bowling average).
Of note, Sanga needs just 2 runs to become the 11th batsman to score 10000 against the top eight teams. The 10 to have already achieved this feat are: Tendulkar, Ponting, Dravid, Lara, Border, Chanderpaul, Steve Waugh, Jayawardene and Gavaskar. Seeing that stat further emphasises my point earlier in the thread that Allan Border was seriously hard done by in the poll.