Think you need a monstrously huge amp to create a big guitar tone? Not necessarily. These days, there are low-wattage (15W or less) amps that sound like huge stadium beasts both in the room and when recorded. The advantage of a low-wattage amp is that you can crank it up (without blowing yourself out of the room or annoying your neighbors), which makes the power section (especially in a tube amp) work harder, the speakers work harder, the cabinet resonates more, and all this combines to produce a huge sound.
This is why Jimmy Page used a low-wattage Supro amp for some of the most blistering Led Zeppelin tones. Other guitarists use the same trick. You can even use your small amp on stage, as long as the venue has a P.A. system and you can mic your amp to get it up loud enough compared to the drums and other instruments. Big 100W amps have a sound all their own — there’s nothing like the visceral impact of a screaming amp stack — and are great if you’re playing a big venue and want to be heard in the very last row or if you need tons of clean headroom, but remember that you can get a very large sound using a smaller amp if you aren’t in a situation where you can crank up a monster amp.