As I've never found an ideal prayerbook for me, I have a few in different languages, so that's a bit annoying and impractical.
My ideal prayerbook would contain:
Morning and Evening prayers with additional things (the Decalogue, the Beatitudes, prayer of the Elders of Optina, basic prayers for the family and dead, Lenten prayer of st. Ephrem, before and after meal etc.)
Prayers before and after the Holy Eucharist
Troparions, Kontakions and Canons of all 12 Great Feasts and Pascha
Akathist to the Theotokos, Holy Spirit, the Guardian Angel
Canon of Repentance
Sunday troparions of 8 tones
And my dream is that it could be in bilingual version: Church Slavonic - Polish or Church Slavonic - Serbian.
However, my greatest need is to have a kind of prayerbook containing prayers before and after the Holy Eucharist and Canons (could be separately) in Polish. Eucharist prayers are one of these exceptions, that I prefer to read them in Polish or Serbian, than in Church Slavonic. And I hope one day these prayers translated into Polish will be published in book form (now I have them printed, but it's not so useful during travels or pilgrims). As for Canons, I have no hope that it will happen. Maybe all these prayers are published in book form in Serbian, however I haven't found such prayerbook yet