While looking at some cleanup in Synaptic package manger for unused packages I thought of seeing what difference it would make to GNOME if I use xdm instead of gdm. Well
1. I saw not so nice startup text display (I am fine with it though)
2. I saw fine black and white mesh screen which is awfully painful for graphical login with thick text box for entering login/password. (I even managed to stand this one)
3. Login was much swift than previous into GNOME. (so it was worth the switch for now)/
4. I could see all the menus icons taskbar etc. so it's good sign.
5. Only thing I missed was shutdown option in GNOME System->Quit (or from the quit button).
The biggest surprise was without anything running I would normally see most of my 4 GB RAM was always in use with GDM which is now drop down to around 700-900Mb even now with Thunderbird, pidgin, firefox on it is at 1.1GB I think to me this is big improvement. (there may some others limitations but for now I thik I will see how it works for me). I past I always saw my system eating away into the 6 GB swap without running much of the applications.
I think I will also try another not so heavy window managers like Enlightenment etc.
The part of inspiration to think about it is DIY I am doing with my homemade Digital Picture Frame out of P-II for which I am trying various linux options after staring the project 2 years back and shelved it with initial success with Windows.
I wish to get more than a digital picture frame out of the DIY possibly low-end media player controllable via remote using lirc. (sounds too ambitious but will give it a go)