Humm 2 12 volt interstates? The more common configuration is 2 Six volt Interestates (U-2200 Work-A-Holic) However no matter nothign wrong with a dual 12 volt set up either, You just need to know for sure which you have before your replace them cause they hook up differently See Twelve volt side of life posts for more (Replace word with number when you search)
Now on to your question:
12 volt batteries can be Starting, Marine, Marine/Deep cycle or.. .DEEP CYCLE (Trolling batteries are deep cycle, as are 12 volt golf car batteries)
For house batteries you want DEEP CYCLE. Not the others.. The reason for this is that the deep cycle battery can survive an "Opps" better (An OPPS is when you accidently over discharge them) The others like to be kept closer to full.
Now, in each of those types you have several choices, I will discuss the big 3 (There are others but I would avoid some and the others are out of sight price wise)
Flooded wet cell (Which you have) Are lowest cost, highest maintence, you need to water them (DISTILLED ONLY PLEASE) and clean them from time to time.
The rest are "Sealed, Valve Regulated Lead Acid Batteries" (Called VRLA or SLA)
Maintence free: Low maintence, you can not add water, they do require occasional cleaning though (I do my MF chassis battery an average of every 2-3 years) Last time was Last week). These are slightly more expensive, Not much different overall life though. (Bit less in some cases, perhaps more in others)
AGM: These are way more expensive and tend to not last as long, They do have the advantage of being able to mount them in "odd" positions, like upside down or on end. They do not come with a "This side up" sticker. SOME (Lifeline to be specific) can take a very rapid recharge. Some can supply higher current too.
I will discuss one special battery here: OPTIMA, Optims is an AGM battery with a sprial wound plate.. Math tells me that you can, at the most, sutff about 3/4 of the battery in the place.. Ratings say only 60%,, What is the other 40%, Wasted air space,
These are more expensive then their more powerful AGM brothers, and worth less.
Home is where I park it!