Firstly, I would say that both Lara and Tendulkar are a cut above any other batsman in the last 15-16 years, with Dravid and Steve Waugh comming closest to them.
Ponting, Kallis, Sehwag, Hayden, Gilly all come a level below the Laras, Tendulkars, Chappells, Richards,Sobers,Gavaskars of the world as far as i am concerned.
But out of the two, i would pick tendulkar as the better batsman.
In One day cricket, it is a no-contest really. Tendulkar ( along with Bevan and Viv) is a cut above anyone else in one day cricket's history.
In Tests, its narrower, but i would give the edge to Tendulkar.
Batting is all about consistency ( not the way a recent crickinfo article described it - consistency as in consistency of getting 50+ or 100+ scores in an innings) and Tendulkar is more consistent than lara career-wise. Tendulkar has had a poor 3 years, largely marred by injury and some directionless batting. Lara went through much the same between 96 and 2001. However, Tendulkar hasnt struggled as badly as Lara had during that patch(where he only had one monster series and a typical '1 huge score followed by half a dozen real poor ones' pattern).
The fact that Tendulkar averages significantly better than Lara away from home and that for most of his career, he's been in a worse boat ( IND batting and WI batting were very much comparable until 97/98, which is almost a decade into Tendulkar's career and 6-7 years into Lara's but WI bowling made the WI a genuine threat everywhere unlike India) would make me give it to Tendulkar - who in my books, has legitimate claims to being the second best batsman since Sir Don AFAIAC.