Anyone know if it is feasible (and practical) to check out Nusa Lembogan's surf breaks for the day but not spend the evening there? Been reading online that it's a quite nice place but that it's also kind of expensive to stay the night?

I don't know about going over for the day and back and still getting some waves but there are other options for the little of cash. Take the local boat over and get them to drop you on the main beach, there are a couple of Losmen there where you can stay for only a few dollars a night right on the beach if memory serves me correctly. You can still walk up the beach each night to Mainski if you feel the need to play some pong and chat. It's beautiful, but like everywhere in Bali at this time don't expect too many solo waves...

You can go over for the day on a day trip, but once you arrive you will be sorry you didn't stay at lest a night to check out the beautiful little island. Great place to stay is Sunset Villa's and Cafe, top spot right on the edge of the ocean, friendly staff, can give you mobile no for contact in Bali . Komang 081 338 595 776

The accomodation is not expensive if you stay on the beach in front of the best surf break called "Shipwrecks". There are several great places to stay for less than $10 US, and you can paddle right out to great surf....or take a boat if you have $1 to spare. I would recommend Danny's or Linda's or Agung's bungalows. You'll want to stay a few days if you love surfing.
I much prefer Nusa Lembongan over Bali, and have stayed there for 6 months before.