Working on the 'how many background processes' idea, this is from one of my machines. It's a dedicated proxy machine, bare minimal Debian install to start with the following extra packages:
- gpm
- ntpd
- sshd
- mysql-proxy
- nullmailer
- dhcrelay
- monit
- snmpd
- vmtools
Install size is 1.5 gig per df -h.
# ps ax
PID TTY STAT TIME COMMAND
1 ? Ss 0:14 init [2]
2 ? S 0:00 [kthreadd]
3 ? S 0:00 [migration/0]
4 ? S 0:00 [ksoftirqd/0]
5 ? S 0:00 [watchdog/0]
6 ? S 0:09 [events/0]
7 ? S 0:00 [cpuset]
8 ? S 0:00 [khelper]
9 ? S 0:00 [netns]
10 ? S 0:00 [async/mgr]
11 ? S 0:00 [pm]
12 ? S 0:01 [sync_supers]
13 ? S 0:01 [bdi-default]
14 ? S 0:00 [kintegrityd/0]
15 ? S 0:02 [kblockd/0]
16 ? S 0:00 [kacpid]
17 ? S 0:00 [kacpi_notify]
18 ? S 0:00 [kacpi_hotplug]
19 ? S 0:00 [kseriod]
21 ? S 0:00 [kondemand/0]
23 ? S 0:00 [khungtaskd]
24 ? S 0:00 [kswapd0]
25 ? SN 0:00 [ksmd]
26 ? S 0:00 [aio/0]
27 ? S 0:00 [crypto/0]
210 ? S 0:00 [ata/0]
216 ? S 0:00 [ata_aux]
264 ? S 0:00 [scsi_eh_0]
278 ? S 0:00 [scsi_eh_1]
315 ? S 0:52 [kjournald]
447 ? S<s 0:00 udevd --daemon
614 ? S 0:00 [kpsmoused]
693 ? S 0:10 [flush-8:0]
869 ? S< 0:00 udevd --daemon
870 ? S< 0:00 udevd --daemon
1125 ? Ss 0:00 /usr/sbin/dhcrelay -q 209.251.178.99 209.251.178.100
1135 ? Sl 4:50 /usr/sbin/monit -c /etc/monit/monitrc -s /var/lib/monit/monit.state
1142 ? Sl 0:02 /usr/sbin/rsyslogd -c4
1162 ? Ss 0:00 /usr/sbin/acpid
1174 ? Ss 1:06 /usr/sbin/ntpd -p /var/run/ntpd.pid -g -u 101:104
1194 ? Ss 0:01 /usr/sbin/cron
1204 ? Ss 0:44 /usr/sbin/gpm -m /dev/input/mice -t exps2
1216 ? S 1:32 /usr/bin/mysql-proxy --proxy-backend-addresses=209.251.178.99:3306 --proxy-address=:3306
1243 ? S 0:00 /usr/sbin/nullmailer-send -d
1259 ? S 2:49 /usr/sbin/snmpd -Lsd -Lf /dev/null -u snmp -g snmp -I -smux -p /var/run/snmpd.pid
1433 ? S 0:21 [vmmemctl]
1582 ? Sl 19:43 /usr/sbin/vmtoolsd
1604 tty1 Ss+ 0:00 /sbin/getty 38400 tty1
1605 tty2 Ss+ 0:00 /sbin/getty 38400 tty2
1606 tty3 Ss+ 0:00 /sbin/getty 38400 tty3
1607 tty4 Ss+ 0:00 /sbin/getty 38400 tty4
1608 tty5 Ss+ 0:00 /sbin/getty 38400 tty5
1609 tty6 Ss+ 0:00 /sbin/getty 38400 tty6
7762 ? Ss 0:00 /usr/sbin/sshd
10037 ? Ss 0:00 sshd: root@pts/0
10039 pts/0 Ss 0:00 -bash
10061 pts/0 R+ 0:00 ps ax
Pipe that into wc -l and get 59. Win 7 is going to have more due to it having to deal with a GUI, printing subsystem, and such.
So I don't think it's a fair to use the number of processes (processi?

) as a reason to get a dual (or higher) core/CPU machine, it all depends on what the expected workload is going to be.
I also believe that Linux is much more efficient than MS Windows (remember, when Vista/7 came out, the recommended machine was considered a mid-range gaming machine), and that most people would rarely need more than a single core machine, or perhaps a dual core Celeron (or equivalent), regardless of the environment used.
<OT>
But the market droids have all but convinced the general public that they
need 'da GeeBees', regardless if they actually do or not, so the demand is there and it makes financial sense for the CPU manufacturers to produce what is being asked for, regardless if it's actually needed or not.
</OT>
Now, if you are building a dedicated gaming box (or plan on doing the virtual machine bit), then a multi-core CPU makes sense. Not many games make use of the abilities yet, but that's changing as time goes on, and getting one can be viewed as a form of future proofing a system.
IMO, YMMV, IANAL: Why do you see so many people driving SUV's on this side of the pond, when the vehicle rarely sees gravel, much less mud? For the most part, they have been convinced that this is what they want/need by marketing, so they get one. The demand is high/bad enough that Porsche and Mercedes both make SUV models.