Hello, I was wondering of a good amp that's a tube. It has to be loud enough to play with drums, bass and vocals. Right now my main focus is pop punk music, but I play every genre imaginable. I've been looking at the Marshall DSL40C, but I'm not sure if that's loud enough to play with drums without putting a mic to it. Thanks!
The DSL40C is a great dynamic amp that works really well with pedals. And at 40 Watts that is more than enough to gig with (as long as you're not playing Wembley or at the Super Bowl)  
Hooper drives the boat chief...
A Traynor YCV50 would also suite your needs well, similar to the Marshall but can be found used for less.
The DSL40C is a great amp. You can further improve the amp tone upgrading the speaker. 
If you can't run with a drummer through the DSL40C, shoot the drummer and get a new one.  One loudazz little amp that can get you kicked out of many bar gigs here in LA.
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis

Guthrie on tone: https://www.youtube.com/watch?v=zmohdG9lLqY