Which is more likely...

[nclib]

I'd say Option 1, though neither is terribly likely.

[Sam Spade]

Neither is likely at all.  I'd give about 0.1% chance of Option 1 and about 0.2% chance of Option 2, because only 5 seats have to be gained, rather than 6.

Here's the way both can happen (without it being too unrealistic):

Dems:  PA:  Casey beats Santorum (obvious) (46)
RI:  Chafee switches parties (unlikely) or Langevin gets into race.  (47)
VA:  Warner runs against Allen and manages to pull off very close win.  (48)
MT:  Gov. Schweitzer runs against Burns, whose scandals become worse during 2006 and wins (49).
Insert your scenario here:
ME:  Olympia Snowe decides to run for governor. (50)
TN, TX, MS:  Retirements plus bitter in-party fights produce a terrible candidate for the general election (that's about the only way I know in those two states).
MO:  Dems come up with a really good challenger (NOT Bob Holden).

Reps:
MN:  Kennedy wins open seat, with Independence Party candidate helping.  (56)
FL:  Jeb Bush (or Crist or Gallagher, both good challengers) run against Bill Nelson and win a substantial (or slight with the challengers) win.  (57)
ND:  John Hoeven runs for the Senate seat and wins a very, very slight victory over incumbent. (58)
NJ:  Corzine picks his bud Bob Menendez for Senate.  Tom Kean wins.  (59)
Insert your scenario here:
NE: Mike Johanns runs against Ben Nelson.  (60)
MD:  Maybe Kwasi gets nominated and someone like Gilchrist runs against him.  Probably unlikely.
WA:  Rossi hangover lasts until 2006. For some reason Cantwell is much less popular than Murray, go figure.
WV:  Robert Byrd collapses and dies, muttering under his breath, "There still ain't no n*ggers in Logan County and there never will be."  Reps. run a good candidate.
WI:  Herb Kohl retires, Tommy Thompson runs.
MI:  A good opponent for Debbie Stabenow comes up (not likely).
Actually, now that I think about it, the Republican chances are probably slightly higher, maybe 0.4%, but who really cares.

[Moooooo]

Neither is very likely, but if I was forced to put money on it.  Id go with Option 2.

[A18]

Neither is very likely, but if I was forced to put money on it.  Id go with Option 2.

[TheresNoMoney]

Neither will happen, but with the way Bush is ruining the economy and Tom Delay is threatening judges, I'd say option 1 is more likely.

[ian]

I'd say Option 1, though neither is terribly likely.

[12th Doctor]

Niether is likely, but Option 2 is far more feasable, assuming that there is not some huge catastophic event between now and then.  Clinton and Dubya have proven that there is no such thing as a mid-term curse anymore.

[J. J.]

It's a choice between 1 to 100 and 1 to 50.  It's slightly more likely for Republican gains of 5 seats, but still very unlikely.

[Smash255]

I would say option 1.  With Abramoff suggesting their are e-mails that deeply connect Delay into the corruption scandal if Delay gets indicted &  if what Abramoff suggests turns out to be as bad as it really is, iy could lead to a backlash against Senate & House Republicans that strongly back Delay.  It probably won't have the impact to give the Dems 6 seats, but I see that as a larger possibility than the GOP picking up 5.