You are correct in your concern. WEP is no longer considered secure and should not be used in most cases. WEP’s main problem is that it uses a static key that, as you surmise, can be captured and cracked. The only advantage to using WEP is that all devices support it. So, if you have older equipment, you can still put WEP on it. It’s better than nothing.
The current strongest wireless security standard is WiFi Protected Access 2 (WPA2) which is based on 802.11 and provides government grade security. WPA2 uses AES encryption and is virtually impossible to crack without physical access to the network.
You still need to use a strong passphrase for WPA2. For sure don’t rely on the default settings of any wireless router and never use WiFi Protected Setup (WPS); it is vulnerable to brute-force attack. Set up your access point manually.