you need to be careful what the cover. it seems that some elective procedures are not always covers, and things like preventions and vaccinations are not always covered either. Its certainly a good idea when it comes to having large surgery done like dentistry and orthopedics, as they do tend to pay up on those. Ticks and alike can be touch and go with the many companies that offer insurance. You should he able to ask your local vet if they have a list of companies so you can compare the many (i think off the top of my head there are over 10 or 12 companies now offering pet insurance)
hope this help.
edit: another thought just reading back, you may stuggle getting insurance on an 8 year old dog now... and find it hard to get them to payout on... best ring around and ask the age limit they will cover. Poodle may be ok, howevre a boxer will not get cover at that age.