Let me guess you are running a default install yes?
Just because you got this or that kernel doesn't mean it is going to be faster, actually it may be fatter.
If you really want your Debian to be faster then start with minimal install, no desktop no tools no nothing just the bare base system, disable installation of suggested and recommended packages, next install the core of xserver, and of course the xserver driver for you video card as start point to have video working, note when you select one of them, all of them will be activate the whole xserver suite, you don't need all that, just the following:
ii xserver-common 2:1.7.7-14 common files used by various X servers
ii xserver-xorg 1:7.5+8+squeeze1 the X.Org X server
ii xserver-xorg-core 2:1.7.7-14 Xorg X server - core server
ii xserver-xorg-input-evdev 1:2.3.2-6 X.Org X server -- evdev input driver
with aptitude is possible to select/deselect the packages,
install a terminal, i suggest rxvt-unicode-lite, you can run it as deamon saving memory, another hint: when you select xserver packages it will also select xterm terminal, but it is bloated. Unselect it.
If you preffer even lighter terminals here a list of some
Select also the X environment and login screen, well you want faster yes? Then pick a lightweight window manager
and here you can have an idea about it
About loging screen i recommend Slim
it is really light and fast.
Having that you will land in a very clean X environment with a terminal only, and then you can install the other programs from there with apt-get or aptitude. Here a list of lightweight applications
About the kernel the only real way to get it really good is compiling it yourself, generic kernels are fat, it does have a lot things that your machine don't need, bring many features anable that you probably will never use, give a serious thought about compiling your own kernel, you want faster yes?
Here a link
about speeding up debian, it is a bit old but there still some useful tips.