TotalHalibut did a great job casting this replay. Here you can see how mass marines/marauders can take out a group of stalkers/sentries without any problem. In SC2, it’s very hard to go wrong with marines and marauders in combination. They work so well together and can fend off most attacks.

xHydrax casts a game between one of the best Protoss players in the world White-Ra and a relatively new face Masq. Here you can see the strength of mass marines.