high memory usage fedora 3

[sid]

Hi..
I am new to linux. I recently installed fedora 3 on my laptop (Dell
latitude D600, 1.6 Ghz, 1 GB RAM and 1 GB swap).This a scenario that i
face. i login into my system for about 30-40 minutes working with
eclipse java ide, evolution, a couple of terminals and one or two other
programs. The memory usage shoots to 90%...i close all applications. and
open just one terminal to run top. I still see more than 70% memory
usage. Why is this. Is there a problem with my installation or do you
guys face the same problem?
The partial output of top after I have closed all applications is given
below. I have used x and M to sort by memory usage  to show you the
processes using significant memory. Plz help...
thanks
Sid

Tasks:  84 total,   1 running,  83 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.7% us,  0.3% sy,  0.0% ni, 98.7% id,  0.0% wa,  0.3% hi,
0.0% si
Mem:   1035268k total,   702652k used,   332616k free,    33816k buffers
Swap:  1108444k total,        0k used,  1108444k free,   419888k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
4393 user      16   0 42604  32m  10m S  0.0  3.2   0:43.35 gnome-panel
3909 root      15   0 79388  30m  10m S  0.3  3.0   6:48.95 X
4395 user      16   0 47832  23m  11m S  0.0  2.4   0:43.44 nautilus
4620 user      17   0 27584  23m 2700 S  0.0  2.3   0:01.47 spamd
4624 user      17   0 27600  23m 2684 S  0.0  2.3   0:03.02 spamd
4621 user      19   0 27556  23m 2692 S  0.0  2.3   0:03.29 spamd
4622 user      18   0 27296  22m 2676 S  0.0  2.3   0:01.88 spamd
4623 user      17   0 27144  22m 2700 S  0.0  2.2   0:01.32 spamd
4618 user      22   0 26108  21m 2624 S  0.0  2.1   0:01.10 spamd
6019 user      23   0  267m  15m 7420 S  0.0  1.5   0:02.30 rmiregistry
7893 user      15   0 35676  12m 8448 S  0.3  1.2   0:06.37 gnome-
terminal
4436 user      16   0 22328  12m 9088 S  0.0  1.2   0:40.32 wnck-applet
4438 user      16   0 21376  10m 8524 S  0.0  1.1   0:11.18 multiload-
apple
4444 user      16   0 21772  10m 8424 S  0.0  1.0   0:03.24 gweather-
applet