Oh, I like the beige one! Actually, I went a little insane this summer - when Fendi opened their flagship store at Ginza Six in Tokyo earlier this year, they offered for sale limited edition selleria Mini Peekaboos in 4 colors. I ended up hiring a personal shopper to go buy one in a blue/violet color and ship it to me (photos in the Peekaboo and the Strap You threads). It was a really extravagant thing to do, but I love it.
They sell matching selleria wallets in both sizes in Japan - the blue one has beige on the inside - and I've been debating purchasing one and having it shipped to me. I've also debated just buying the blue version available in the US and not incurring the additional fees to have the Japanese version shipped to me. But, really, I like all of the colors. The grey one you selected is gorgeous and practical, I agree. With something that's handled so much, the color will definitely hold up well. Can't wait to see it!