There are a lot of things to consider when making the decision between a university or college program, but when you boil it all down, there are really four main differences between the two:
In general, a university undergraduate degree will take longer to finish than a college program. Most undergraduate degrees take about three to five years to complete, while a college diploma program can range from around nine months to two or three years. If you want to get out of school and into the workforce as quickly as possible, than college is likely the right choice for you.
The structure of the university versus college school day is also something to consider. In many university programs, students have a lot of leeway in creating their own schedules, resulting in days where you might have three or four hours of classes, followed by days with none.
College classes, on the other hand, are often fairly fixed and the school days can be pretty intensive. Similar to high school in some ways, a college schedule might have you at your desk from 9 a.m. to 4 p.m. all week. If you're juggling school and work, this could wreak havoc with your schedule.
University programs are not only longer than college programs, they're also more expensive overall. Not only are you paying for an extra year or two of education, but yearly costs at a university can be double what you'd pay for a college course. For example, in the course I took (a four-year joint program between the University of Winnipeg and Red River College) I paid about $2,000 tuition for a year at the college and over $3,500 for a year at the university. Over three or four years, this difference in tuition can definitely add up. Do the math and figure out your finances before beginning a program of study.
This is, perhaps, the most notable difference between university and college. Simply put, a university education tends to be highly academic, even abstract - it teaches you how to think critically about the world around you. On the flip side, a college education focuses more on applied knowledge and hands-on learning - college teaches you how to do something in the world.
This obviously carries over into classroom instruction. In university, you'll likely sit in a room with 200 other people, listen to a professor talk, and then do some readings and hand in a few highly intellectual essays and assignments. In college, classroom instruction often takes the form of the students learning how to do something and then getting up and actually doing it - taking apart a car engine, designing a magazine advertisement, building a computer.
Both forms of learning have pros and cons - university grads sometimes find themselves unsure exactly what it is they're trained to do in the "real world", whereas college graduates might find their program was too focused and wish they could have gotten a taste of a broader range of topics.
For the best of both worlds, you might want to consider entering one of the growing number of joint programs being offered through university and college partnerships across the country. In these types of programs, you generally spend a year or two in college to earn a diploma, and then another couple of years taking university courses to earn a bachelor degree. This balanced route might best prepare you for the future by fostering both practical and intellectual skills.
Because universities tend to be bigger institutions, with more course options and longer programs, they've come to be seen as the more prestigious post-secondary choice. In fact, in the eyes of some employers a university degree is still seen as being more valuable than a college diploma. Just having it on your résumé might be enough to get you a job, when put up against a college-trained applicant.
There are also plenty of statistics saying university grads make more money in their lifetimes than college grads, although this might have more to do with the initial career choices those grads are making than with where they went to school. After all, a doctor (who went to university) is going to make more than a mechanic (who went to college). On the other hand, a college-trained journalist and a university-trained journalist might still make about the same amount of money in the field.
In the end, it really all comes down to personal preference - which school and program do you feel will give you the best launch-pad for your future? The best way to find this out is to do lots and lots of research - talk to former students to find out if they think they wasted their time taking a certain program, and ask potential employers what kind of an education they'd suggest.
Even the historical differences are blurry. There is both Harvard College and Harvard University. The current fashion is to upgrade to University in name for many schools as it appears to have more prestige.
The general rule is that a University contains several Colleges, like a College of Science, a College of Arts, or even a College of Medicine, but this is not always the case. Some Universities contain Schools of Arts, Schools or Sciences. Some colleges contain Divisions of Arts, etc. While most Universities have graduate programs, some do not and some colleges (Dartmouth) have them also. (Although the Dartmouth College/University is a historical issue around the Dartmouth College Case and government interference when they tried to take it over and rename it Dartmouth University.)
There is no rule now, nor was there a rule back in the day.
The formal difference is that a university has multiple faculties within it (i.e. schools or colleges). Normally this means that universities have graduate and/or professional schools. There are several universities which are called colleges for historical reasons (Dartmouth, Boston College, William & Mary) and a few places which are colleges, but call themselves univerisities to try to sound more prestigious.
Originally, a university was a school that had a graduate program. A college did not have a graduate program. This is still almost true today, although there are some instances where schools have started or stopped offering graduate programs but have never changed their names.