[My Personal Dread Build]

Ogris makes it go boom every time instead of half the time (if multishot gives you 2 arrows every time, 30% thunderbolt per arrow gives you a 49/51 split of explosion to not explosion).

[Frost Or Excaliber]

While I can't disagree with what the pro-excalibur camp are saying in terms of excalibur having more diversity and varied use, having started to play both a little later in game (levelled mag, then rhino, then trinity, then ash before getting silly and starting to float around multiple frames) I've found frost to be an easier start.  He's a little tankier and thus more survivable, at lower levels his meh special ability damage still does the job (which is either kill stuff, or at least get you out of trouble by stopping it from killing you), the snow globe, while a one trick pony, is a very nice trick pony and pretty much always has a place in defense, mobile defense (which is sometimes one of the tougher missions when you first go through a system), and even in survival (as well as for reviving teammates).  Although he shines against grineer and corpus, the slowdown effect on infested helps out at the earlier levels.  As a first frame, you don't have toworry about endgame - there will be plenty of other warframes.

 

The only caveat is his speed - he is S-L-O-W.  If you have a clan, or friends to play with who will wait for you, or if you tend to orient well in game space and don't obsess about opening or exploring everything then you should be ok - but it can suck having a slow frame in a PUG where everyone else is flying through the tileset.

[What Is The Countdown Timer For?]

I've got to second Buuli - the game made a huge jump for the better when I got brave and went online with other players.  Sure there are some uber equipped folks who try to rush through low level stuff (in those cases, try to avoid getting stuck in fights and don't lose time opening crates or lockers; just try to keep up - you'll get good affinity by staying close), but by playing with experienced players you get a chance to see what can be done and tackle harder content which equals better mods (which equals being able to handle tougher content).  Other than survival (and maybe the defenses), you aren't really messing it up for someone else - if someone really wants to solo, they can switch out of online mode.