If you plan on buying wraps (my dd was wrapped up tight for sleeps until she was about 6 months old) I'd definately recommend that you try and get the largest size possible. I got a few that were 100cm x 80cm and within no time at all they were not big enough to keep DD wrapped tightly. The wraps, both flanelette and muslin, do come in 120cm x 120cm and they were brilliant. The flanelette ones I used were made by Smart Swaddle and the muslin ones were made by Bubba Blue.
Ooh how exciting, reading this thread has got me all excited again about packing my hospital bag (last time I did it the day I was due, might do it a bit earlier this time).