Blanche Lincoln (D-inc): 43 (45)
Bill Halter (D): 35 (33)
Other: 7 (6)
Undecided: 15 (16)
(MoE: ±5%)
Halter has made a bit of an ascent over the past couple of weeks, pulling within single digits of Lincoln for the first time after previously stalling at a gap of 12 points. Pay close attention to that "Other" number, which presumably are the votes that tea-flavored Democrat D.C. Morrison is targeting. If no one wins 50% on May 18th, this sucker is going nuclear to a runoff on June 8th. In that event, this could be a race where time may be on Halter's side.
And for the general election match-ups:
Blanche Lincoln (D-inc): 42 (43)
John Boozman (R): 52 (50)
Undecided: 6 (7)
Rasmussen also has some numbers that, while not looking anything quite like this, at least corroborate the idea that Halter is less of a general election liability than Lincoln.