This post is part of our Hottest Products of 2007 feature. Also check out our other Hottest Products of 2007 posts and let us know which product you think is the greatest thing since sliced bread.

I was a reluctant BlackBerry purchaser earlier this year. Urged on by a change in email systems at work, I found I needed one to keep up with internal goings on. I planned to retain my trusty Treo 650 as my "main" handheld -- my one true smartphone -- and just use the BlackBerry occasionally as needed.

But oh, the lure of the "crackberry." I'm hooked! My old Treo 650 from Palm (NASDAQ: PALM) is starting to seem like R2D2 of Star Wars fame. It's still my trusted friend, but a little dated and not quite able to perform the heroics of my World Edition BlackBerry. Shares of Research In Motion (NASDAQ: RIMM), maker of the BlackBerry, have surged this year from $42 to $107 in good part on its success with the 8800 series.

Most important for me, the BlackBerry updates automatically and doesn't need to be synced with my computer -- if a meeting is rescheduled, I can find out en route. It is lightning fast, and emails are all there waiting for me when I have a minute to check -- even on the subway where I can't get a signal.

Most reviews praise the BlackBerry 8800 Series' battery life, but I actually find the battery lasts longer on my Treo, given the way I use the devices. I think the BlackBerry's phone, which is often criticized in reviews, is clearer and easier to use than my Treo.

So what do I use my Treo for now? For one, it's easier to look up all the information that is saved on the device -- contacts, memos, notes -- the touchscreen truly is a wonderful thing. My Treo has a camera, and I've stored lots of photos there. Most of all, I carry it for the instant messaging function. Colleagues and contacts know that is a great way to reach me if I'm not at my desk. The BlackBerry's instant messaging system just doesn't cut it from what I can tell.

For now, I carry the two devices most places I go. But already, after only a few months, I can see the BlackBerry is gaining an edge. In a few months, next time I'm trying to travel light, I can already see, my trusty Treo may be the device I leave home.

If you've had some experience with this product, let us know about it. Or if you know of something else that you think is one of the Hottest Products of 2007, feel free to tell us about that as well.