178 quid for a trip to Berlin? Woah, I hope that includes 3-star or 4-star accomodation and breakfast, otherwise it is a lousy deal. Flights from London or Manchester to Berlin can be had for 50 GBP return and a night in a hostel bed is approx. 20 EUR.
Berlin is still pretty cheap compared to London or Paris, it is possible to get a decent meal for 15 EUR excluding drinks.
Taxi from the airport is not very practical, Berlin is very spread out. Depending on where you are going you can easily pay 30+ EUR for the ride. It is much better to take the bus or the S-Bahn to your destination, it is only 2.10 EUR per person from Tegel and 2.80 EUR from Schoenefeld for the ride.
http://www.berlin-airport.de/EN/ReisendeUndBesucher/AnUndAbreise/AnfahrtBusUndBahn/SXF/OeffentlicheSXF.html
http://www.vbb-fahrinfo.de/hafas/query.exe/en?
From: Flughafen Schoenefeld Terminal
To: (street of your hotel)
or
From: Flughafen Tegel (Berlin)
To: (street of your hotel)