When you're giving your opinion but don't want to say it too strongly (because you're being polite or because you don't feel strongly about it), you can say "I would ___". Examples of this are:
I would probably look around for a better deal.
I would go with the higher-priced model.
You often use "I would ___" when you're giving someone else advice, and you're not the person making the final decision. It usually sounds polite and helpful.
There are also different uses for "I would" such as "I would like...":
I would like an iced tea, please.