one of them i found during the trip to Jakarta - a hardcovered doa selawat with couple name printing, and they packaged in a nice box too. a little pricey tapi sangat2 bermanfaat, kan. i've seen similar idea locally, they give a plain Yaasin. nothing fancy tapi berguna esp di malam Jumaat :)
tasbih is my favourite of all non-edible doorgift. apart from being handy, again it's something useful. easier to keep too - gantung je :) but do consider cost of packaging too and please note both gifts only sesuai for Muslim guests.