The ADSL modems which I have seen ... even the ones with only a single Ethernet port - will handle quite a number of simultaneous logical connections. The number of at least 32 is in my head.
The practical effect of this is that you do NOT need a router, an Ethernet (packet store and forward) "switch" is plenty adequate in most situations.
Let's address a couple of things here....
First, the number of 32 is not correct.
Not wishing to get into technical detail, your ADSL router has two IP addresses, one public, one private.
On the private side, the number of available IP addresses available on your internal network is dependant on the subnet mask you configure.
By default, ADSL routers tend to come out of the box configured with a 255.255.255.0 (/24) subnet mask from the 192.168/16 RFC1918 range. This gives you 253 usable addresses on your network (the IP address of your router is already taken into account in this figure).
Should you wish to, you may reconfigure your router to use the 10/8 RFC1918 range (255.0.0.0) , this will give you 16,777,213 usable addresses (the IP address of your router is already taken into account). Although in practical purposes, your average cheap ADSL router will probably have a few issues if you start to scale to that level... but then I'd hope you would be able to afford something rather better than an ADSL line with that many devices on your home network !
The second point is the term "modem" ....
A modem is a single user device, plugged into your computer via a USB cable.
A router is a multi-user device that presents an ethernet port on the user side. A router incorporates an embedded modem. It also has Wifi and other circuitry inside to enable it to provide connectivity services to your network independent of reliance on any computer.
Therefore, stating "you do NOT need a router" is incorrect. If you want to share your internet connection amongst multiple users (either via Ethernet or WiFi), then you
DO need a router.
using an Ethernet switch
Yes, switches are great. Just make sure you don't create routing loops ! Easy to create, equally easy to avoid, but a nightmare to troubleshoot and identify.
Also, other than risking routing loops, there are many good reasons not to daisy chain switches unless you know what you're doing. So try to future proof a bit when buying... for example, rather than a 4 port switch, buy an 8 port one etc.
I avoid wireless / WiFi whenever possible because it requires administration, configuration, assignment of a name used by clients, and assignment of a password - if you want any security. A wired (Ethernet) connection has NONE of these challenges.
I agree with this. If you can avoid the hassles of WiFi, particularly keeping on top of the security aspect, then turn it off ! As an added benefit, performance over Ethernet cable will always be better than Wifi.