I spent 3 nights in Kuta and 3 nights in Ubud.
Bali is worth visiting. Is it worth visiting for the girls? Maybe, but I didn't know enough to go to the right places when I visited. I did get laid, but it wasn't my best lay in Indonesia.
Kuta is a fucking dump. Sky Garden, the most popular club there, is shit.
Hard Rock Cafe is full of Asian tourists, but it was half empty when I went.
I heard a lot of good things about Seminyak and club Mint which is located there, but went there on the wrong night mid week, so it was closed.
Ubud is fantastic, definitely worth visiting. It's not about looking for girls, although there are girls out there - both Indo and foreign. I haven't seen anything like Ubud anywhere else in the world. It just puts your mind at ease, makes your forget about all the shit. I highly recommend the downhill cycling tour to see Balinese villages and rice fields.
For girls, I recommend Jakarta. A lot of educated, upper class girls who are promiscuous, love foreigners and speak good English. The night life there is just fucking insane.
My Indonesia trip report