Hero's Mod? Aint that a AMXX plugin for Counter-Strike? You can use that with the Counter-Strike version you get with Half-Life, and even with the Counter-Strike retail package. If i were you (if you don't have the game yet) get the Half-Life Package, not the CS Package.
If you get CS or Half-Life, either way, the hero's amxx plugin will work on both versions. But as said above, just get Half-Life. I bought Half-Life: Blue Shift, and with the cd-key i was able to play mostly all Half-Life games, including Counter-Strike and Condition Zero (i believe)