Business Cards: Does Size Matter?

What are your thoughts on effective business card design? 

Does SIZE really matter? 
Over the last few years, I've acquired quite the collection of unique business cards that come in so many different shapes, styles, designs, textures, materials and sizes. At the end of the day though, what's important? And can your message (your contact information, and what you do) get lost when a business card is just too artistic and creative? Does it depend on your industry? 

If you venture too far away from the classic size of a business card, does it make it harder for a person to save and keep that card?

Or even simple changes like rounded corners vs. the classic crisp sharp corners. Let me know what you think!

I welcome designers and communications professionals to share their insight here. I would also like to hear from the customer perspective (people on the receiving end).