Ok, I've had the phone for a full week now and here's my mini review:
Moving from the Nec e606 to the Nokia 7600 was a great idea. I now have a battery life that last longer than a day and that doesn't require recharges or battery swaps just because I called a couple of people and sent a text message!
The battery life on the 7600 lasted 3 days happily without recharge during my first 3 days which is good to say I was playing with it a lot (new toy, must play

) and trying out it's features.
The camera on the 7600 is a lot better than the e606 on both photo and video and also seems to respond a lot quicker too. In other words, it's usable and the photos are recognisable too. The camera also seems to perform very well in low light conditions using it's night time setting. I tried this in a club, casino and in a field. All photos were fine and the e606 didn't even manage to get anything other than darkness.
The 7600 also has a handy camera button at the top of the phone too which can be used to take photos quickly instead of going through it's menus. This is very handy and means you get more chance to take a photo or video of something as it happens.
The 7600 fits nicely in to your pocket, unlike the e606 which looked like you were carrying a breaze block around.
I admit that the 7600 is still slightly bigger than some phones, but it does fit neatly in the palm of your hand and when in your pocket is almost not visible.
The weird shaping isn't to everyone's liking, but it's certainly grown on me and my mates.
The MP3 ringtones are fun but can sometimes be a little quiet. This is sorted by using some freeware software I found to increase the volume of the MP3 files and they are fine now.
The voice dial is excellent and there doesn't seem to be the 10 number limit imposed on it like some phones. This is very handy when being used with my Jabra BT200 headset as I can make a call while driving.
Bluetooth! Yes it's got it and yes it actually works. This is a nice addition for me as my e606 was
meant to have this but it could only be used for transfering files and even then I never managed to get it working!
The 7600 has full Bluetooth and it works great. I have tried this with mates phones, sending files etc. and also with my new Bluetooth headset, the Jabra BT200 which I strongly recommend!
The software on the 7600 is also excellent. Unlike the e606 it doesn't seem to slow down, doesn't seem to crash and doesn't have that annoying feature of the signal dropping and no phone features being available while deleting text messages.
The 7600 has 28 meg of Ram for storage, which is excellent. It's so far holding many games, 7 videos, 6 MP3 files, my full phone book and about 25 voice dials and still has about 10.5 meg left.
Linking the 7600 to your PC is easy thanks to the Nokia PC suite and can be done via cable, IR or BT. I have happily synched it with my Outlook and it also seemed to update the time and date settings while on their too.
Another benefit of this phone is that it's not been 'Threealised'. In other words you can upload games and Java applications to the phone via your PC without having to buy them from Three's walled garden. This means that instead of paying 50p every so often for a license to play you can download free games from the net (keep it legal though) and then upload them to your phone. This is something that people have been trying for a long time with the other Three phones. (Take that Three!

)
I currently have the Moto game, Bomberman and loads of others too which is a lot better than the e606's complete lack of games and requirement of pay per play at stupid recurring prices.
The 7600 as a phone (which is what it is) works well. The call quality is clear and it's actually quite comfortable to use, despite it's looks. The only thing that lets the calls down on this phone is the Three network.
My overall feeling is that when I bought the Nec e606 on Three I was stupid! It's a shoddy phone that's a pain in the arse to use. Only now that I have moved to the Nokia 7600 have I realised how nice it is to use a decent phone again. The software works, the phone has all it's advertised features and it's reliable.
My advice is if you have any other Three handset then sell it (or smash it) and get yourself to Carphonewharehouse now with £150 and buy the Nokia 7600 on Threepay NOW. Sell the Threepay simcard on Ebay for about £30 and enjoy your new phone. (they are selling more and more of these as people realise how much better they are) This is definately the best phone on the Three network at the moment.
The Nokia 7600 is also easily unlocked and can be used on any network, so if you want to make some cash then buy a few of them at £150 and sell them at £200 each as sim free. Also selling the sim cards at £30 each racks up your profit