Wow, it's quite expensive in Canada! It most definitely isn't worth it, I say, but neither are most cosmetic mods for cars. Just a personal touch, really.
I don't know how much standard plates cost in my state, because if I recall, the cost is included in registration fees and that's maybe $100 USD or so total. To get a personalized plate in CT, first you must register the car and receive standard plates then pay an additional ~$90 for the new personal plates. So, all is said and done, it's probably close to $200 or so in Connecticut and renewing registration every 3 years costs $120 regardless of whether the plate is standard or personal.