Finnland Insitut (our conference place) is located just at the Friedriechstrasse train station, one of the biggest train/metro stations in Berlin, easily communicated with all other stations (it is a next station to Hbf, or the very main station).
Very close to this place we have tens, if not hundreds of pubs and and restaurants on both sides of the river (you have the Spree close by). Also, very short distance (5 min on foot) to Island of Museum, to Brandenburg Gate (10-15 min on foot) and the Jewish Museum (15-20 min on foot).
The closest hotels there (just meters away) are:
Some 7-10 minutes on foot away you can find
Hotels and Hostels for those on low budget:
Hotel Meininger (some 10 minutes on foot; recommended)
Baxpax Downtown (10 min on foot)
Generator Berlin Mitte (15 min on foot)
Hotel Novalis ( 15 min on foot)
Zarenhof Hotels & Apartaments Berlin Mitte ( 15 min on foot)
Eastener Hostel (15 minutes on foot)