If You Had Six Weeks in London...

Day 3, depart London.
Day 41, return to London.

+1. Travel a lot. It's not called "Let's See Europe" for nothin'. Cote D'Azure, Ibiza, Montenegro/Croatia, Prague/Budapest, Barcelona, Rome.

Bars in London:
ECC -Experimental Cocktail Club. Gerrard St, Chinatown. -branch of the Paris bar, great drinks. Hidden(ish) bar next to the Far East restaurant. Smallish, going on weekends without a reservation will result in disappointment.
Vista at the Trafalgar -nice view
The Box -crazyass fetish place where you will drop lots of money. Reservations are basically required. Last time I went Megan Fox and her entourage sauntered in before me.
Sometimes in shoreditch there's a cool event called 'the Blitz'

Since you're at LSE you will undoubtedly end up at places like Penthouse and Zoobar. Do not go more than once if you can help it.

Shopping:
The summer sales are winding down but you can still find good deals at Harrod's, Harvey Nicholls, Selfridges and some of the flagship boutiques. If not, Jermyn St. offers good shirts at a great value.

For museums/gallery, the basic ones are: Natural History Museum, Science Museum, Victoria & Albert (all of which are handily close together), British Museum, Royal Academy, Tate Mordern

Depending on where you're from, maybe some sort of sporting event. For footbally, unless you've declared your allegiance already in terms of friendliness, affordability and availability I'd suggest Fulham. There's also rugby and cricket if you're here during the summer.

As for bars, I'd recommend Mark's Bar which is downstairs from Hix Soho (which is a pretty decent restaurant albeit not cheap). I went to Callooh Callay in Shoreditch last week and that was very pleasant.

For restaurants if I were you I'd go for the sort of thing that you might not get anywhere else, or at least where you're from. I'd try a curry house in the East End somewhere, not Brick Lane though, maybe Tayyabs or, if you're feeling flush Benares. Or a gastropub such as Great Queen Street, the Anchor and Hope or the Harwood Arms. I've been meaning to go to Viajante as well and there is of course Heston Blumenthal's place at the Mandarin Oriental.

Thrift stores are really a bit hit and miss. They say you can get good stuff at the charity shops in the nicer areas (Chelsea, Marylebone etc) but as far as menswear goes I've never had any luck. There is, however, Old Hat in Fulham which deals in vintage/second hand mens tailoring. I visited at the weekend and could have got myself a couple of Huntsmans for about £300 if only all my limbs were about 6" shorter. There are a few nice boutiques up Lambs Conduit Street, which is nice for a quiet afternoon and away from the tourists.

It all sort of depends when you're coming I suppose and what you're into.

Friday happy hour in Soho with the after work crowd followed by bar hopping in Camden / Islington / Shoreditch

Saturday afternoon in Borough Market / Marylebone buying great (albeit expensive) ingredients for a special dinner. Then spending the rest of the afternoon with friends on a sunny pub terrace getting pissed, resulting in your food going off and having to bin the whole lot.

Sunny Sundays having dim sum then drinking wine on Primrose Hill watching the cute girls drinking away hangovers

Well, thats how I spend many of my weekends...

K

lol, was about to post something along this lines.

was gonna say I'd hop the first flight to the 'dam and return six weeks later! hitting up both actually in a few weeks, can't wait

Day 1: Get on a train at Paddington, Euston, Waterloo, Kings Cross, etc.
Day 2: ????