MacBook Air :: Can't Choose Between MB MBP And Air?

Well I have some money from a research grant to buy a new laptop as my trusty old Dell Latitude D610 is really starting to give up the ghost. I decided after I bought my Pro that I really didn't want to go back to crappy PC laptops, and I'm really psyched after the notebook update to get one of the new models, but I really don't know which.

Anyway, I went down to the Apple Store today to play with new the new MBs/MBPs. Everything was going pretty well really - until I realised how bloody heavy and wide the damn thing is! It feels quite a bit heavier than my Dell even though it's only 250g more. I virtually always have my laptop with me, and the more I think about it, the more the weight factor might become a deal-breaker for me. Actually, not having my laptop in the bag for the first time in a while has really made me realise how heavy the damn thing is - I'm not sure I want to put up with that for the next couple of years.

If I'm honest, the Air is really what I want. But I'm not sure how well it will cope with my daily routine, which generally has some of the following:

Running scientific programming applications - post-processing data, Fourier transforming it, etc. I've been really encouraged by the two-page thread on these forums saying that MBA is capable of doing this sort of thing. The 6MB L2 cache sounds really good.Casual gaming is something I've not been able to do with my D610, and it'd be nice if it were capable of running some lower end games (for example CS:S, HL2) even at reduced resolution. I've heard the 9400M should be good enough for this, but maybe I'll wait on that. Clearly the MBP is more cut out for this.

As you can see from my sig, I like photography quite a bit. Most of my photo work is done on the Mac Pro, but often I'll find myself out and about and would like to download the photos; it would be nice to be able to run Lightroom.

I listen to a heck of a lot of music, but I don't think there will be a problem here.
I'm virtually always online, web browsing and e-mail etc but again I don't think this will be a problem.

I think I can live with only the single USB port, and the lack of a DVD drive doesn't bother me greatly. Ethernet is a bit of a pain - ideally I'd like gigabit ethernet, so I'd need to give this some thought. Nothing I have has a Firewire port on it. Generally the only thing that gets plugged into my laptop is the iPhone and my headphones, so I think I'm good on that front.

The MB is also a sensible option, with most of the pros of the Air without the drawbacks. Weight is slightly less than my existing laptop, and I guess it's probably just as portable. It also has the option of a higher 2.4GHz processor, and more in terms of expandability. Not sure whether I really want this or not, though.