Here's a bibliography I did a little while ago on this period - the focus is on church history during this period, but there's a lot on general conditions then too. As Head Serf says, it really depends on what place you're talking about. Things were better in Spain than in France, for example.
Blair, J. The church in Anglo-Saxon society Oxford: Oxford University Press 2005
Brown, P. The rise of western Christendom: triumph and diversity 200-1000 AD 2nd. Ed. Oxford: Blackwell 2003
Carver, M., ed. The cross goes north: processes of conversion in northern Europe, AD 300-1300 York: Boydell 2003
Chapman, J. Saint Benedict and the sixth century Westport: Greenwood Press 1971
Christys, A. Christians in al-Andalus, 711-1000 Richmond: Curzon 2002
Collins, R. Visigothic Spain, 409-711 Oxford: Blackwell 2004
Cusack, C. Conversion among the Germanic peoples London: Cassell 1998
Daniel-Rops, H. The church in the Dark Ages London: Phoenix 2001
Dunn, M. The emergence of monasticism: from the Desert Fathers to the early Middle Ages Oxford: Blackwell 2000
Fletcher, R. Moorish Spain London: Weidenfeld & Nicolson 1992
Fletcher, R. The barbarian conversion: from paganism to Christianity Berkeley, CA: University of California Press 1999
Gameson, R., ed. St Augustine and the conversion of England Stroud: Sutton 1999
Hillgarth, J., ed. Christianity and paganism, 350-750 rev. ed. Philadelphia, PA: University of Pennsylvania Press 1986
Houwen, L. and MacDonald, A., eds. Alcuin of York: scholar at the Carolingian court Groningen: Forsten 1998
Hylson-Smith, K. Christianity in England from Roman times to the Reformation 1. from Roman times to 1066 London: SCM 2001
MacMullen, R. Christianity and paganism in the fourth to eighth centuries New Haven; London: Yale University Press 1997
Markus, R. Gregory the Great and his world Cambridge; New York: Cambridge University Press 1997
McKitterick, R., ed. Carolingian culture: emulation and innovation Cambridge: Cambridge University Press 1994
Moorhead, J. Theoderic in Italy Oxford: Clarendon 1993
Olsen, T. Christianity and the Celts Oxford: Lion 2003
De Paor, L. Saint Patrick’s world: the Christian culture of Ireland’s Apostolic Age Blackrock: Four Courts 1993
Pelikan, J. The Christian tradition: A history of the development of doctrine 3. The growth of medieval theology (600-1300) Chicago: University of Chicago Press 1978
Richards, J. The popes and the Papacy in the early Middle Ages 476-752 London: Routledge and Kegan Paul 1979
Wallace-Hadrill, J. The Frankish church Oxford: Clarendon 1983
Watt, J. The church in medieval Ireland 2nd. Ed. Dublin: Macmillan 1998
Webster, L. and Brown, M., eds. The transformation of the Roman world AD 400-900 London: British Museum Press 1997
Wood, I. The missionary life: saints and the evangelisation of Europe Harlow; New York: Longman 2001
A couple of other books that have very good descriptions of everyday life in this period are:
Smith, T. De Gratia: Faustus of Riez’s treatise on grace and its place in the history of theology (sorry, I don't have publication details for this)
George, J. Vanantius Fortunatus Oxford: Clarendon 1992