Mysore Veggie
1689 Middlesex St, Lowell, MA
(978) 452-8700

South Indian vegetarian restaurant, along with the usual North Indian cuisine too. They have some fusion dishes too (I still havnt come across a properly "fused" fusion restaurant - they all seem to be lost in translation). I prefer the Udipi next door (almost).
The food was ok - idli/sambar, and some multi-vegetable uttapam. 5/10
They have a Sunday lunch buffet.

Omkar - closed.
1717 Middlesex St Unit 3, Lowell, MA,01852

Vegetarian. Got tricked into going there once.
Tried the buffet. I cook better than that. - 3/10

Update: the place closed.

Masalaa Boston (aka Masalaa)
786 Boston Road,Billerica,MA 01821
(978) 667 3443

South Indian vegetarian restaurant. I prefer the food at Udipi.
The food is generally ok for a South Indian restaurant.
Masala dosa - 5/10.

Udupi Bhavan Lowell
1717 Middlesex St, Lowell, MA
(978) 654-6653

Generally nice food. Vegetarian only. 6/10
I like their "Chana bhatura" (ironical, given that this is a South Indian restaurant). The chana (aka chana masala) is a bit creamy though, but tastes ok. Some other chana masalas elsewhere have an overdose of spices and an overbearing raw-spicy taste.