I have lived in Barnsley for all my life (I am 19).
The reason I like Barnsley is that everything is close together.
For example..

SHOPPING
I go to Leeds or Sheffield shopping, and I don't know my way around. All the shops are far apart from each other, and I can never find places to eat, especially healthy places to eat. In Barnsley town centre, the shops are a 2 minute walk from the bus station. They are all on one street leading up to The Mall shopping centre, where the rest of the shops are. There are a few shops on streets around the main street, and an indoor market area coming off the main shopping street. So it is all tightly packed and easy to navigate around. There are lots of places to eat too. There is a KFC, pubs and restaurants, fish and chip shops, jacket potato places, sandwich shops, and a few Greggs too.

NIGHTLIFE
The nightclubs in the town centre are again close to one another, which again is an advantage. When I go elsewhere, I dont know where any of the good nightlife is, as they all seem streets apart, or taxi rides apart! In Barnsley, there are 3 main rows of streets for the nightlife. There is a row where the "starter pubs" are situated, near the Town Hall, you then walk down the hill, and this street has the nightclubs which are open from around 9pm - 2am. You then walk around the corner and the next street has the nightclubs which are open from around 11pm - 4am. At the end of this street is Barnsley's Superclub Escapade. Although Barnsley is small, I prefer the Saturday nights here than anywhere else I've been for a night out. Wednesday nights (student night) and Friday nights are not really busy, but the Saturdays are really fun. There is a lot of entertainment to choose from - Joseph Bramahs (wetherspoons), CHE bar (cuban themed nigthclub), Quasimodos (rock music), Chicagos (gay bar - TUESDAY especially), Escapade (with VIP area, theme nights, and either up to date music OR cheesy pop - choose your room).

THE PEOPLE
I hear that Barnsley has a bad reputation, mainly because of the football club. However, people in Barnsley are actually really nice. If you get lost, people are always happy to help, people smile back at you. I have been to other places where no one smiles back, and they are too busy to help with questions.

THINGS TO DO
There isn't a great deal to do in Barnsley besides the shopping and nightlife experience, but I will list what there is:
Cannon Hall farm and museum - has an animal farm, huge gardens to walk around or hold picnics, museum. Holds activity days for children such as craft days, baking days etc.
Locke Park - a huge park in the town centre. Has nice gardens for a walk or picnic and children's play area. Also has a cafe which opens in the summer.
Bowling Alley - in Carlton, Barnsley
Metrodome - swimming and gym, town centre
Dorothy Hyman Stadium - in Cudworth, Barnsley. Gym, squash courts, badmintin courts, astrosturf, running track
Oakwell - football stadium, Town centre.

And thats about it. The town centre has good transport links with trains straight to Nottingham, Meadowhall / Sheffield, Leeds. And buses straight to Wakefield / Doncaster / Rotherham.