Childcare/childminder is often a qualified adult who looks after other children in their own home (not the child's home, the carers home) . They can take them from birth right through to teenagers. Most offer childcare from around 7am-7pm Monday-Friday. Most will do before and after school drop off and pick ups. You usually pay weekly or monthly in advance.
Creches are usually groups of children looked after by several carers. They are often situated near workplaces or university campuses (this may be the best option for you) as they usually only take children from birth up to compulsory school age (5 years). Im not sure on their operating hours you will need to ask each one specifically because some may offer childcare to emergency service staff who work shifts.
Nurseries are similar to crèches really. They operated from the beginning of the working day (from 6am in some places) through to the evening (some as late as 8pm I believe). They have several staff usually in a large building separated into age groups. 3 and 4 year old children are entitled to free nursery care and some 2 year olds but its limited on how many hours are free (someone else will know im sure).
Some Nurseries are attached to a local primary school but having a place at a particular nursery wont guarantee you a place at that school when your child starts full time school.
Some private nurseries will take children from birth - 5 years, others only take 3+4 year olds.
Nannies/Au-Pairs are pretty much the same thing. You pay privately for someone to look after your child in your own home. Au-pairs generally have their own room and meals provided by you whereas Nannies may go home at the end of the day. Although some people have a Nanny who has their own room.
Pre-school is basically from age 4 usually and its a more structured form of childcare. Its often based on a normal school day (starts around 8.45am finishes around 3pm) . My children's pre-school had a uniform and they were taught basic letters, numbers, reading their name etc. They had a sports day to attend and Christmas play. It was like a mini school. These are generally attached to private schools you can also use the 'free nursery hours for 3 and 4 year olds ' towards your fee's so its discounted from the full fees.
Its been a few years since I've had to use childcare as my children are now at primary school so although the advice I've given is reasonably correct (I believe) there may be differences/changes over the last few years that I've missed out as I'm unaware of them. 
As to what is best for you I cannot say. They all have their pro's and con's. I would recommend you start with your University and see if they have a crèche on site. If not then contact the local education authority for the area you will be living and ask them to send you details of local nurseries/childminders etc and take it from there.