Informal:
* J'aimerais avoir: This is the most common and polite way to say it.
* J'aimerais bien avoir: This adds a slight emphasis on desire.
* J'aimerais beaucoup avoir: This emphasizes a strong desire.
* J'aurai bien aimé avoir: This implies a wish that can't be fulfilled.
* J'aurais bien aimé avoir: This implies a regret about something not happening.
More casual:
* J'veux avoir: This is a very informal and casual way to say it, and should only be used with close friends.
Examples:
* J'aimerais avoir un café, s'il te plaît. (I would like to have a coffee, please.)
* J'aimerais bien avoir une pizza ce soir. (I would really like to have a pizza tonight.)
* J'aimerais beaucoup avoir un chien. (I would really love to have a dog.)
* J'aurai bien aimé avoir plus de temps pour voyager. (I would have liked to have more time to travel.)
* J'aurais bien aimé avoir un scooter. (I would have loved to have a scooter.)
Remember that using the familiar form ("tu") requires a close relationship with the person you're speaking to. If you are unsure about using the familiar form, it's always best to use the formal form ("vous").