There is no such thing as the perfect mobile phone — and there probably never will be for two reasons.

First, as in all else, what is right for one may not be — and in the cell phone world, probably isn’t — right for another. Second, trying to balance functionality and portability necessitates ideal-busting compromise on the part of mobile phone manufacturers.

I’ll list my off-the-cufff requirements for the cell phone I want to carry permanently, and you’ll see both these limiting reasons come to play:

• GSM and not locked to a single provider;
• Bluetooth, WiFi, 3G, USB connectivity;
• Full QWERTY keyboard;
• Small and light so that the right front pocket of my Levis survive six months;
• A camera that takes real pictures without the grain (this, of course, is a must for parents of small, and therefore unpredictably photogenic, children);
• Full cross-platform syncing capability;
• A full SIP stack that allows VoIP calling over wireless networks.

This phone does not — and never will — exist.

But Nokia is coming close — very close.

I’ve been alternating between two of the ceaselessly innovating Finnish company’s new-generation mobile phone products lately: the E61, which is unfortunately not widely available in North America due to mobile service carrier shortsightedness, and the more recently released (and more readily available) N80 Internet Edition (or N80i, which is different from the N80 that has been available but includes no VoIP support).

Between the two, you have something close to cell phone nirvana. Each individually — though at the top-of-the-mobile-heap — comes up a bit short.

I’ve gone through about a dozen phones in the past three years. Almost all of them are Nokia, in no small measure because my friend Dameon Welch-Abernathy, who works for the company and is an enthusiastic (and knowledgeable) fanboy for the Helsinki home team products, manages to convince me each time I am looking to change.

Of all of them, the E61 and N80 are the best.

I’ve been carrying the E61 around with me since September. It looks just like the E62 offered by Cingular in the U.S., but, unlike Cingular’s brain-dead model, comes with full WiFi and SIP capability built in. The mobile phone industry has been predicting the release of a so-called “Blackberry-killer” for years, and the E61 could be it. It’s sleek, powerful, includes a great keyboard for small thumbs like mine, and, unlike any of RIM’s offerings, includes a SIP stack and is actually relatively dependable as a cell phone (Blackberry’s abysmal cell phone killed the deal for me).

I used the E61 constantly. I have made and received hundreds of calls through various VoIP channels. including the outstanding Truphone service, and Voxilla’s Communigate Pro and Asterisk telephone servers (relatively easy to set up by consulting Martin Dindos’ excellent “how-to”). For email and instant messaging, there is no better mobile than the E61 on the market.

But . . .

The E61 is just a bit too big in my pocket. It’s WiFi range comes up short, too often losing SIP registration (not unlike an on-the-road dead-spot over a cell). The phone has no camera (a feature that, just a couple of years ago, seemed superfluous but has nearly become as indispensable as an ATM card). As a Mac user, the device’s shortcomings in OSX connectivity (no SMS access, for example) are bothersome. And, even more annoying, the phone’s left-side voice recording buttons become engaged at even the slightest pressure, leaving my phone with dozens of recordings “requested” by the fabric of my pants’ pocket.

If you can live without thumb-tip QWERTY (increasingly hard for me to do), the N80 is a significant improvement.

It’s a bit thicker than many of the less-capable mobiles available, but fits comfortably in my jeans. It’s easy-to-use 3-megapixel camera fits my non-pro needs well. It doesn’t come with oddly placed buttons that mysteriously turn themselves on. And its WiFi range (802.11g. Really!) is outstanding (I’ve yet to lose registration through my home router once, even in the downstairs hillside dungeon that serves as home-office).

Martin’s instructions for the Nokia E-series and asterisk apply to the N80 as well, and, though definitely cumbersome without the aid of a full keyboard like the E61′s, establishing connectivity is manageable.

Signing up with Truphone (currently in beta) could not be easier: send an SMS with the word “TRU”, wait a second for a reply SMS containing a clickable installation URL. You’re done. The phone also comes pre-installed with an applet that similarly facilitates registration with Gizmo Project’s SIP service.

Dreaming is easy and I’ve come up with two improvements for both the E61 and N80:

• These are both WiFi phones, so, when on a network, you would think you can easily manage settings over a web browser, right? No. Adding a small web server to the phones would allow it, and save countless people countless configuration hours. Ideally, one would establish a WiFi connection via the phones’ keypad and all other settings would be configurable on the browser (much like a VoIP telephone device is configured).
• Give us more universal peripheral connectivity. Nokia’s monstrous “pop-port” connector makes it very difficult to use, for example, a headset other than one manufactured by Nokia. This is a serious limitation because the lesser-quality stereo ear-plug/mic combo that comes with the phone is uncomfortable and makes for difficult conversations. How hard is it to include a standard 3.5 mm headset jack? Please do so.

But these are just nits. The more important matter here is that, finally, at least one cell phone manufacturer is coming to grips with the fact that the future of communications blends the mobile and the IP worlds. For the most part, Nokia is getting it right. And it’s probably only a matter of time before the other manufacturers — and even intransigents like Cingular and Verizon — are forced to jump in.