...in India, at least.
That being said, let me elaborate. Pune is a culturally strong city and is, without doubt, the cultural capital of Maharashtra. At the same time it is a university city. There are a huge number of colleges here, and thats what makes it a bachelor’s paradise.
Now what does a bachelor want most - good food - preferably free, an occasional drink or two, ample opportunity for mindless romance, places to visit after midnight and hep crowd. Barring the last (excuse me Puneites), Pune offers him everything else at a discount.
The city itself is quite inexpensive. Inspite of the previous paragraph, I must stress that the city is extremely safe - you can actually enjoy a midnight movie at a decent place. Commuting is a problem if you are not used to travelling by buses - hailing an autorickshaw is usually a basis for negotiation. Most people can converse in Hindi, english is a strict no-no.
The city has numerous places to visit / shop around. MG Road, Swargate, University are nice places to hang out in. The best time to visit is during the Ganesh Chaturthi festival. Pune grows on you - if you are visiting or driving through, you may not enjoy this place, but if you plan to stay put for sometime, this is the place for you.