Which MacBook Pro 'old' 15.4" unibody 2.4 or new 13.3" 2.53?

[Trivial rock]

So Im in the market for a new MacBook Pro I have 2 options:
New 13.3" MBP 2.53Ghz
'Old' 15.4" Unibody 2.4Ghz MacBook Pro

Both in the UK will cost me ~ £1000 the first from Apple with student discount and the second off eBay.

Which one should I go for? The 'old' 15.4" has a discreet GPU as well as the 9400M.

The new 13.3" MBP has a 7hr battery and .13Ghz increase in processor speed as well as 4GB of DDR3 as opposed to 2. Also Ill get a free upgrade to SL in Sept (save p&p).

Which one will preform better? I use office, the net, handbrake and Im a casual gamer. RA3 and Oblivion im playing at the moment. Like I said its casual, im not worried about getting high frame rates or maxing out the settings, just as long as it is smooth.

Thanks for your help in advance.

 

[aleksandra.]

I think the deciding factor between new or previous generation MBP is the battery life. If you need it, get a new one. Otherwise you get more with last generation (for the same price, that is).

 

[Trivial rock]

The battery life is a big thing for me, but the main question I guess is how will the 9400M cope with casual gaming?

 

[Philflow]

Maybe it helps to know the 13" MB gets about 2200 in 3dmark06.

While the MBP gets about 5800.

 

[cube]

I just got the prev gen 15" to ensure I won't have to lug a 17" for ExpressCard, plus keep the ability to swap batteries.

I always wanted a PC Card slot in a 12" or 13", but Apple never offered that.

But I must tell you. This 15" is BIG. It doesn't seem practical to carry (from the size, not the weight). I haven't tried yet.

So, I keep on waiting for ExpressCard on a 13"

 

[Trivial rock]

I do prefer the 13" for the portability and the battery, the fact it cant be removed (easily) is really not an issue for me. Thanks for the 3d marks, that does say ALOT. However I wonder how that compares to real world experiences?
Any casual gamers out there who game a couple of hours a week and use the 9400M?

Thanks for all the input